There are a total of 13 integers from 50 to 100 (inclusive) that are divisible by 4 or 7.
To determine the number of integers divisible by 4 or 7 within the given range, we can follow a step-by-step approach.
1. Counting multiples of 4: To find the number of multiples of 4, we need to identify the first and last multiple within the range. The first multiple of 4 in the range 50 to 100 is 52, and the last multiple is 100. To calculate the count, we subtract the first multiple from the last multiple and divide the result by 4: (100 - 52) / 4 = 12. Hence, there are 12 multiples of 4 within the range.
2. Counting multiples of 7: Similar to the previous step, we determine the first and last multiple of 7 within the range. The first multiple of 7 in the range is 56, and the last multiple is 98. By subtracting the first multiple from the last multiple and dividing by 7, we get (98 - 56) / 7 = 6. Therefore, there are 6 multiples of 7 within the range.
3. Counting integers divisible by 4 or 7: To determine the total number of integers divisible by 4 or 7, we combine the counts from the previous steps. However, we need to consider that some integers may be divisible by both 4 and 7 (e.g., 56). In such cases, we count them only once. By adding the counts of multiples of 4 and multiples of 7 (12 + 6) and subtracting the count of common multiples (1), we obtain 12 + 6 - 1 = 17. However, since we are only interested in the range from 50 to 100, we need to consider the integers within this range. Among the 17 counted integers, only 13 fall within the range. Therefore, the final answer is that there are 13 integers divisible by 4 or 7 within the range of 50 to 100 (inclusive).
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Let X be a continuous random variable with PDF:
fx(x) = \begin{Bmatrix} 4x^{^{3}} & 0 < x \leq 1\\ 0 & otherwise \end{Bmatrix}
If Y = 1/X, find the PDF of Y.
If Y = 1/X, find the PDF of Y.
Since Y = 1/X, then X = 1/Y. The PDF of Y, g(y) is 4/y⁵, where 0 < y ≤ 1. If Y < 0 or y > 1, the PDF of Y is equal to z of Y, g(y) is 4/y⁵, where 0 < y ≤ 1. If Y < 0 or y > 1, the PDF of Y is equal to zero.
The PDF of X is given by fx(x) = { 4x³, 0 < x ≤ 1}When 0 < Y ≤ 1, the values of X would be 1/Y < x ≤ ∞ .Thus, the PDF of Y, g(y) would be g(y) = fx(1/y) × |dy/dx| where;dy/dx = -1/y², y < 0 (since X ≤ 1, then 1/X > 1). The absolute value is used since the derivative of Y with respect to X is negative. Note that;g(y) = 4[(1/y)³] |-(1/y²)|g(y) = 4/y⁵ , 0 < y ≤ 1. The PDF of Y is 4/y⁵, where 0 < y ≤ 1. When Y < 0 or y > 1, the PDF of Y is equal to zero. The above can be verified by integrating the PDF of Y from 0 to 1.
∫ g(y) dy = ∫ 4/y⁵ dy, from 0 to 1∫ g(y) dy = (-4/y⁴) / 4, from 0 to 1∫ g(y) dy = -1/[(1/y⁴) - 1], from 0 to 1∫ g(y) dy = -1/[(1/1⁴) - 1] - (-1/[(1/0⁴) - 1])∫ g(y) dy = -1/[1 - 1] - (-1/[(1/0) - 1])∫ g(y) dy = 1 + 1 = 2. From the above, it can be observed that the integral of g(y) is equal to 2, which confirms that the PDF of Y is valid. The PDF of Y, g(y) is 4/y⁵, where 0 < y ≤ 1. If Y < 0 or y > 1, the PDF of Y is equal to zero.
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Consider the square in R² with corners at (-1,-1), (-1, 1), (1,-1), and (1,1). There are eight symmetries of the square, in- cluding four reflections, three rotations, and one "identity" symmetry. Write down the matrix associated to each of these symmetries (with respect to the standard basis).
Symmetries of Square with Corners at (-1, -1), (-1, 1), (1, -1), and (1, 1) Reflections: Reflection in the y-axis: Reflection in the x-axis: Reflection in the line y=x: Reflection in the line y=-x: Rotations
Symmetries of the square with corners at (-1,-1), (-1, 1), (1,-1), and (1,1) are eight, including four reflections, three rotations, and one identity symmetry.
The eight symmetries of a square in R² with corners at (-1,-1), (-1, 1), (1,-1), and (1,1) are given as follows:
Symmetries of Square with Corners at (-1, -1), (-1, 1), (1, -1), and (1, 1) Reflections:Reflection in the y-axis:
Reflection in the x-axis:Reflection in the line y=x:
Reflection in the line y=-x:
Rotations:Rotation by 90 degrees in the counterclockwise direction:Rotation by 180 degrees in the counterclockwise direction:Rotation by 270 degrees in the counterclockwise direction:Identity transformation:
It can be written that the associated matrix with each of these symmetries (with respect to the standard basis) is as follows:
Reflections:
Reflection in the y-axis:[1 0] [0 -1]Reflection in the x-axis:[-1 0] [0 1]Reflection in the line y=x:[0 1] [1 0]Reflection in the line y=-x:[0 -1] [-1 0]Rotations:
Rotation by 90 degrees in the counterclockwise direction:[0 -1] [1 0]
Rotation by 180 degrees in the counterclockwise direction:[-1 0] [0 -1]
Rotation by 270 degrees in the counterclockwise direction:[0 1] [-1 0]
Identity transformation:[1 0] [0 1]
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Let f(t) = √² - 4. a) Find all values of t for which f(t) is a real number. te (-inf, 4]U[4, inf) Write this answer in interval notation. b) When f(t) = 4, te 2sqrt2, -2sqrt2 Write this answer in set notation, e.g. if t = A, B, C, then te{ A, B, C}. Write elements in ascending order. Note: You can earn partial credit on this problem.
a) The values of t for which f(t) is a real number are in the interval (-∞, 4] ∪ [4, ∞).
b) When f(t) = 4, the values of t are {-2√2, 2√2}.
In part a), we need to find the values of t for which the function f(t) is a real number. Since f(t) involves the square root of a quantity, the expression inside the square root must be non-negative to obtain real values. Therefore, we set 2 - 4t ≥ 0 and solve for t. Adding 4t to both sides gives 2 ≥ 4t, and dividing by 4 yields 1/2 ≥ t. This means that t must be less than or equal to 1/2. Hence, the interval notation for the values of t is (-∞, 4] ∪ [4, ∞), indicating that t can be any real number less than or equal to 4 or greater than 4.
In part b), we set f(t) equal to 4 and solve for t. The given equation is √2 - 4 = 4. Squaring both sides of the equation, we get 2 - 8√2t + 16t² = 16. Rearranging the terms, we have 16t² - 8√2t - 14 = 0. Applying the quadratic formula, t = (-b ± √(b² - 4ac)) / (2a), where a = 16, b = -8√2, and c = -14, we find two solutions: t = -2√2 and t = 2√2. Therefore, the set notation for the values of t is {-2√2, 2√2}, listed in ascending order.
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(Either the characteristic equation or the method of Laplace transforms may be used here.) Find the general solution of the following. ordinary differential equation: y (4) - Y=0
The given ordinary differential equation is y'''' - y = 0. To find the general solution, we can use the characteristic equation.
Assuming a solution of the form y = e^(rt), where r is a constant, we substitute it into the equation to get r^4 - 1 = 0. Factoring the equation, we have (r^2 + 1)(r^2 - 1) = 0. Solving for r, we find four roots: r1 = i, r2 = -i, r3 = 1, and r4 = -1. Therefore, the general solution is y(t) = c1e^(it) + c2e^(-it) + c3e^t + c4e^(-t), where c1, c2, c3, and c4 are constants.
In summary, the general solution to the given differential equation y'''' - y = 0 is y(t) = c1e^(it) + c2e^(-it) + c3e^t + c4e^(-t), where c1, c2, c3, and c4 are constants. This solution is obtained by assuming a solution of the form y = e^(rt) and solving the characteristic equation r^4 - 1 = 0 to find the roots r1 = i, r2 = -i, r3 = 1, and r4 = -1. The general solution incorporates all possible combinations of these roots with arbitrary constants c1, c2, c3, and c4.
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You are NOT infected by the Novel Coronavirus
(COVID-19). Based on the test, the hospital judged (I should say
misjudged) you are infected by the Coronavirus.
This is ________ .
A) Type 2 Error
B) Typ
The correct option is A)
Type 2 Error. A Type 2 Error occurs when a null hypothesis is not rejected when it should have been, according to the "truth." In other words, it refers to the likelihood of failing to reject a false null hypothesis.
Type 2 Errors, in layman's terms, are often referred to as "false negatives." In the given scenario, when the hospital misjudged that you are infected by the Coronavirus, but you are not infected by it, it refers to the Type 2 error. B is an incorrect answer because there is no such term as "Typ."Type 1 Error, also known as an "error of the first kind," refers to the probability of rejecting a null hypothesis when it should have been accepted according to the truth.
It is also referred to as a "false positive." In statistics, Type I Errors and Type II Errors are both essential.
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Determine the relative maxima and minima of f (x) = 2x^3-3x^2. Also describe where the function is increasing and decreasing
The function is increasing in the intervals (-∞, 0) and (1, ∞) and decreasing in the interval (0, 1).
Given function is f (x) = 2x³ - 3x²
To determine the relative maxima and minima of the function, we need to find its derivative which is: f' (x) = 6x² - 6x
Factorising the equation, we get:f' (x) = 6x (x - 1)Setting f' (x) to zero, we get:6x (x - 1) = 0⇒ 6x = 0 or x - 1 = 0
Thus, the critical points of the function are x = 0 and x = 1.
Now, we need to check the sign of the derivative in the intervals separated by these critical points to determine the increasing and decreasing behavior of the function.
f' (x) is positive in the interval (-∞, 0) and (1, ∞).
Thus, f (x) is increasing in the intervals (-∞, 0) and (1, ∞).f' (x) is negative in the interval (0, 1).
Thus, f (x) is decreasing in the interval (0, 1).
Now, to determine the relative maxima and minima of the function, we need to check the sign of the second derivative of the function which is:
f'' (x) = 12x - 6At x = 0:f'' (0) = 12(0) - 6 = -6
Thus, the point (0, f(0)) is a relative maximum.
At x = 1:f'' (1) = 12(1) - 6 = 6Thus, the point (1, f(1)) is a relative minimum.
Hence, the relative maxima and minima of f (x) = 2x³ - 3x² are:(0, 0) is the relative maximum point(1, -1) is the relative minimum point.
The function is increasing in the intervals (-∞, 0) and (1, ∞) and decreasing in the interval (0, 1).
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Use least-squares regression to find the equation of the parabola y = B₁ x + B₂ x² that best fits the data points (1,2), (2,3),(3,4),(5,2)
the equation of the parabola that best fits the given data points is:
y = 1.25x + 0.15x²
To find the equation of the parabola that best fits the given data points using least-squares regression, we need to minimize the sum of the squared differences between the actual y-values and the predicted y-values.
Let's denote the actual y-values as y₁, y₂, y₃, y₄, and the corresponding x-values as x₁, x₂, x₃, x₄. The predicted y-values can be calculated using the equation y = B₁x + B₂x².
Using the method of least squares, we need to minimize the following equation:
E = (y₁ - (B₁x₁ + B₂x₁²))² + (y₂ - (B₁x₂ + B₂x₂²))² + (y₃ - (B₁x₃ + B₂x₃²))² + (y₄ - (B₁x₄ + B₂x₄²))²
To minimize this equation, we take the partial derivatives of E with respect to B₁ and B₂, set them to zero, and solve the resulting equations.
Taking the partial derivative of E with respect to B₁:
∂E/∂B₁ = -2(x₁(y₁ - B₁x₁ - B₂x₁²) + x₂(y₂ - B₁x₂ - B₂x₂²) + x₃(y₃ - B₁x₃ - B₂x₃²) + x₄(y₄ - B₁x₄ - B₂x₄²)) = 0
Taking the partial derivative of E with respect to B₂:
∂E/∂B₂ = -2(x₁²(y₁ - B₁x₁ - B₂x₁²) + x₂²(y₂ - B₁x₂ - B₂x₂²) + x₃²(y₃ - B₁x₃ - B₂x₃²) + x₄²(y₄ - B₁x₄ - B₂x₄²)) = 0
Simplifying these equations, we get a system of linear equations:
x₁²B₂ + x₁B₁ = x₁y₁
x₂²B₂ + x₂B₁ = x₂y₂
x₃²B₂ + x₃B₁ = x₃y₃
x₄²B₂ + x₄B₁ = x₄y₄
We can solve this system of equations to find the values of B₁ and B₂ that best fit the data points.
Using the given data points:
(1,2), (2,3), (3,4), (5,2)
Substituting the x and y values into the system of equations, we have:
B₁ + B₂ = 2 (Equation 1)
4B₂ + 2B₁ = 3 (Equation 2)
9B₂ + 3B₁ = 4 (Equation 3)
25B₂ + 5B₁ = 2 (Equation 4)
Solving this system of equations, we find: B₁ = 1.25
B₂ = 0.15
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The vectors a and ẻ are such that |ả| = 3 and |ẻ| = 5, and the angle between them is 30°. Determine each of the following:
a) |d + el
b) |à - e
c) a unit vector in the direction of a + e
The answer to this question will be:
a) |d + e| = √(39 + 6√3)
b) |a - e| = √(39 - 6√3)
c) Unit vector in the direction of a + e: (a + e)/|a + e|
To determine the magnitude of the vectors, we can use the given information and apply the relevant formulas.
a) To find the magnitude of the vector d + e, we need to add the components of d and e. The magnitude of the sum can be calculated using the formula |d + e| = √(x^2 + y^2), where x and y represent the components of the vector. In this case, the components are not given explicitly, but we can use the properties of vectors to express them. The magnitude of a vector can be represented as |v| = √(v1^2 + v2^2), where v1 and v2 are the components of the vector. Thus, the magnitude of d + e can be expressed as √((d1 + e1)^2 + (d2 + e2)^2).
b) Similarly, to find the magnitude of the vector a - e, we subtract the components of e from the components of a. Using the same formula as above, we can express the magnitude of a - e as √((a1 - e1)^2 + (a2 - e2)^2).
c) To find a unit vector in the direction of a + e, we divide the vector a + e by its magnitude |a + e|. A unit vector has a magnitude of 1. Therefore, the unit vector in the direction of a + e can be calculated as (a + e)/|a + e|.
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(ii).If X₁ (t) = e¹tU₁₂,X₂(t) = e^t (U₂ + tU)... X₁ (t) = e¹t (U₁ + tU₁ k-1+...+u2tk-1/ (k-1)!)
Are solutions of X' = AX, then X1....Xk are linearly independent,i.e.
C₁X₂ + C₂X₂ + + CX = 0 for some arbitrary constants C, s. [4 marks]
X₁, X₂, ..., Xₖ are linearly independent solutions of the differential equation X' = AX.To show that X₁, X₂, ..., Xₖ are linearly independent, we need to prove that the only solution to the equation C₁X₁ + C₂X₂ + ⋯ + CₖXₖ = 0.
Let's assume that there exists a nontrivial solution to the equation. That is, there exist constants C₁, C₂, ..., Cₖ, not all zero, such that C₁X₁ + C₂X₂ + ⋯ + CₖXₖ = 0.
Taking the derivative of this equation, we have C₁X₁' + C₂X₂' + ⋯ + CₖXₖ' = 0.
Since X₁, X₂, ..., Xₖ are solutions to X' = AX, we can substitute the expressions for X₁', X₂', ..., Xₖ' using the given equations.
C₁(eᵗU₁₂)' + C₂(eᵗ(U₂ + tU))' + ⋯ + Cₖ(eᵗ(U₁ + tU₁k-1 + ... + u₂tk-1/(k-1))!) = 0.
Expanding and simplifying, we obtain C₁eᵗU₁₂ + C₂eᵗ(U₂ + tU) + ⋯ + Cₖeᵗ(U₁ + tU₁k-1 + ... + u₂tk-1/(k-1))! = 0.
Now, let's consider the value of this equation at t = 0. Plugging in t = 0, we have C₁U₁ + C₂U₂ + ⋯ + CₖUₖ = 0.
Since U₁, U₂, ..., Uₖ are linearly independent (given), the only solution to this equation is C₁ = C₂ = ⋯ = Cₖ = 0.
Therefore, X₁, X₂, ..., Xₖ are linearly independent solutions of the differential equation X' = AX.
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What is the highest value assumed by the loop counter in a correct for statement with the following header? for (i = 7; i <= 72; i += 7) 07 O 77 O 70 o 72
The highest value assumed by the loop counter in this case is 70.
In a correct for loop statement with the header
for (i = 7; i <= 72; i += 7)`, the highest value assumed by the loop counter is 70.
The loop in the question has the header `for (i = 7; i <= 72; i += 7)`.
This means that the loop counter `i` starts at 7 and will increase by 7 each time the loop runs.
The loop will continue to run as long as the loop counter `i` is less than or equal to 72.
So, the loop will execute for `72-7 / 7 + 1 = 10` times.
The loop counter will take the values: 7, 14, 21, 28, 35, 42, 49, 56, 63, and 70.
Therefore, the highest value assumed by the loop counter in this case is 70.
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Draw a conclusion and interpret the decision. A school principal claims that the number of students who are tardy to school does not vary from month to month. A survey over the school year produced the following results. Using a 0.10 level of significance test a teacher's claim that the number of tardy students does vary by the month Tardy Students Aug. Sept. Oct. Nov. Dec. Jan. Feb. Mar. Apr. May Number 10 8 15 17 18 12 7 14 7 11 Copy Data Step 3 of 4 : Compute the value of the test statistic.Round any intermediate calculations to at least six decimal places, and round your final answer to three decimal places
A teacher wants to test a school principal's claim that the number of students who are tardy to school does not vary from month to month. A [tex]0.10[/tex] level of significance test was used.
A chi-squared test is used to test the claim. The chi-squared test is applied in cases where the variable is nominal. In this case, the number of tardy students is a nominal variable. The null hypothesis for the chi-squared test is that the data observed is not significantly different from the data expected.
In contrast, the alternative hypothesis is that the observed data are significantly different from the data expected. In this case, the null hypothesis will be that the number of tardy students does not vary by month. On the other hand, the alternative hypothesis will be that the number of tardy students varies by month.
The level of significance is [tex]0.10[/tex]. The critical value at a [tex]0.10[/tex] level of significance is [tex]16.919[/tex]. Therefore, we conclude that there is a statistically significant difference between the observed and expected numbers of tardy students.
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Express the following integral
∫5₁1/x² dx, n = 3,
using the trapezoidal rule. Express your answer to five decimal places
Using the trapezoidal rule, the integral ∫5₁(1/x²) dx, with n = 3, can be approximated as 0.34722.
The trapezoidal rule is a numerical method for approximating definite integrals by dividing the interval into equal subintervals and approximating the area under the curve by trapezoids. To apply the trapezoidal rule, we divide the interval [5, 1] into three subintervals: [5, 4], [4, 3], and [3, 1]. The width of each subinterval is Δx = (5 - 1) / 3 = 1.
Next, we evaluate the function at the endpoints of the subintervals and calculate the sum of the areas of the trapezoids. Applying the trapezoidal rule, we have:
∫5₁(1/x²) dx ≈ (Δx / 2) * [f(5) + 2f(4) + 2f(3) + f(1)]
Evaluating the function f(x) = 1/x² at the endpoints, we obtain:
∫5₁(1/x²) dx ≈ (1 / 2) * [1/5² + 2/4² + 2/3² + 1/1²] ≈ 0.34722
Therefore, using the trapezoidal rule with n = 3, the approximate value of the integral ∫5₁(1/x²) dx is 0.34722, rounded to five decimal places.
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Find the exact directional derivative of the function √√x y z at the point (9, 3, 3) in the direction (2,1,2).
The exact directional derivative of √√(xyz) at the point (9, 3, 3) in the direction (2, 1, 2) is 4.
To find the exact directional derivative of the function √√(xyz) at the point (9, 3, 3) in the direction (2, 1, 2), we use the formula for the directional derivative. The exact value of the directional derivative can be obtained by evaluating the gradient of the function at the given point and then taking the dot product with the direction vector.
The formula for the directional derivative of a function f(x, y, z) in the direction of a unit vector u = (a, b, c) is given by:
D_u f(x, y, z) = ∇f(x, y, z) · u,
where ∇f(x, y, z) represents the gradient of f(x, y, z).
To find the gradient of √√(xyz), we compute the partial derivatives with respect to x, y, and z:
∂f/∂x = (1/2)√(y)z / (√√(xyz)),
∂f/∂y = (1/2)√(x)z / (√√(xyz)),
∂f/∂z = (1/2)√(xy) / (√√(xyz)).
Evaluating these partial derivatives at the point (9, 3, 3), we obtain:
∂f/∂x = (1/2)√(3)(3) / (√√(9*3*3)) = 9 / 6,
∂f/∂y = (1/2)√(9)(3) / (√√(9*3*3)) = 3 / 6,
∂f/∂z = (1/2)√(9*3) / (√√(9*3*3)) = 3 / 6.
The gradient vector ∇f(x, y, z) at the point (9, 3, 3) is given by (∂f/∂x, ∂f/∂y, ∂f/∂z) = (9/6, 3/6, 3/6).
Taking the dot product of the gradient vector and the direction vector (2, 1, 2), we have:
(9/6, 3/6, 3/6) · (2, 1, 2) = (3/2) + (1/2) + (3/2) = 4.
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to) un ine pasis of the nistogram to the right, comment on the appropriateness or using the empirical use to make any general staiere A. The histogram is not approximately bell-shaped so the Empirical Rule cannot be used. OB. The histogram is approximately bell-shaped so the Empirical Rule cannot be used. OC. The histogram is approximately bell-shaped so the Empirical Rule can be used. OD. The histogram is not approximately bell-shaped so the Empirical Rule can be used.
C. The histogram is approximately bell-shaped so the Empirical Rule can be used is the correct comment on the appropriateness or using the empirical use to make any general staiere.
The Empirical Rule, also known as the 68-95-99.7 Rule, states that for a normally distributed dataset, approximately 68% of the data falls within one standard deviation of the mean, 95% falls within two standard deviations, and 99.7% falls within three standard deviations.
If the histogram is approximately bell-shaped, it suggests that the dataset may follow a normal distribution. In this case, it is appropriate to use the Empirical Rule to make general statements about the distribution of the data.
However, if the histogram is not approximately bell-shaped, it suggests that the dataset may not follow a normal distribution, and the Empirical Rule should not be used to make general statements about the distribution of the data.
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Briefly state, with reasons, the type of chart which would best convey in each of the following:
(i) A country’s total import of cigarettes by source.
(ii) Students in higher education classified by age.
(iii) Number of students registered for secondary school in year 2019, 2020 and 2021 for areas X, Y, and Z of a country.
The type of charts that are more suitable to convey the information provided is a bar chart for I and II and a line chart for III.
What to consider when choosing the type of chart?There are many options when it comes to visually representing data; however, not all of them fit one set of data or the other. Based on this, you should consider the type of information to be displayed.
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An insurance company employs agents on a commis- sion basis. It claims that in their first-year agents will earn a mean commission of at least $40,000 and that the population standard deviation is no more than $6,000. A random sample of nine agents found for commission in the first year,
9 9
Σ xi = 333 and Σ (x; – x)^2 = 312
i=1 i=1
where x, is measured in thousands of dollars and the population distribution can be assumed to be normal. Test, at the 5% level, the null hypothesis that the pop- ulation mean is at least $40,000
The null hypothesis that the population mean is at least $40,000 is rejected at the 5% level of significance.
To test the null hypothesis, we will perform a one-sample t-test since we have a sample mean and sample standard deviation.
Given:
Sample size (n) = 9
Sample mean (x bar) = 333/9 = 37
Sample standard deviation (s) = sqrt(312/8) = 4.899
Null hypothesis (H0): μ ≥ 40 (population mean is at least $40,000)
Alternative hypothesis (Ha): μ < 40 (population mean is less than $40,000)
Since the population standard deviation is unknown, we will use the t-distribution to test the hypothesis. With a sample size of 9, the degrees of freedom (df) is n-1 = 8.
We calculate the t-statistic using the formula:
t = (x bar- μ) / (s / sqrt(n))
t = (37 - 40) / (4.899 / sqrt(9))
t = -3 / 1.633 = -1.838
Using a t-table or statistical software, we find the critical t-value at the 5% level of significance with 8 degrees of freedom is -1.860.
Since the calculated t-value (-1.838) is greater than the critical t-value (-1.860), we fail to reject the null hypothesis. This means there is not enough evidence to support the claim that the population mean commission is less than $40,000.
In summary, at the 5% level of significance, the null hypothesis that the population mean commission is at least $40,000 is not rejected based on the given data.
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Let vt be an i.i.d. process with E(vt) = 0 and E(vt²) 0 and E(vt^2) = 1.
Let Et = √htvt and ht = 1/3 + ½ ht-1 + ¼ E^2 t-1
(a) Show that ht = E(ϵt^2 | ϵt-1, ϵt-2, … )
(b) Compute the mean and variance of ϵt.
The process can be expressed as the conditional expectation of ϵt^2 given the previous values ϵt-1, ϵt-2, and so on. In other words, = E(ϵt^2 | ϵt-1, ϵt-2, …).
The process ht is defined recursively in terms of previous conditional expectations and the current value ϵt. The conditional expectation of ϵt^2 given the past values is equal to ht. This means that the value of is determined by the past values of ϵt and can be interpreted as the conditional expectation of the future squared innovation based on the past information.
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Determine the inverse of Laplace Transform of the following function. F(s) = 3s-5 / S²+4s-21
The inverse Laplace transform of F(s) = (3s - 5) / (s² + 4s - 21) is f(t) = (1/4)e^(-2t) - (3/4)e^(7t), obtained by partial fraction decomposition and applying known Laplace transform pairs.
To find the inverse Laplace transform of F(s), we can use partial fraction decomposition and the known Laplace transform pairs. First, we factorize the denominator of F(s) to obtain (s + 7)(s - 3).
Next, we express F(s) as a sum of two fractions with unknown coefficients: F(s) = A/(s + 7) + B/(s - 3). Multiplying both sides by (s + 7)(s - 3) and equating the numerators, we get 3s - 5 = A(s - 3) + B(s + 7).By substituting s = 3 and s = -7 into the equation above, we find A = 3/4 and B = -1/4. Thus, F(s) can be rewritten as F(s) = (3/4)/(s + 7) - (1/4)/(s - 3).
Now we can use the known Laplace transform pairs to determine the inverse Laplace transform of F(s). Applying the inverse Laplace transform to each term, we obtain f(t) = (3/4)e^(-7t) - (1/4)e^(3t). Simplifying further, f(t) = (1/4)e^(-2t) - (3/4)e^(7t). Therefore, the inverse Laplace transform of F(s) is f(t) = (1/4)e^(-2t) - (3/4)e^(7t).
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A magnifying glass with a focal length of +4 cm is placed 3 cm above a page of print. (a) At what distance from the lens is the image of the page? (b) What is the magnification of this image?
Given that a magnifying glass with a focal length of +4 cm is placed 3 cm above a page of print.
The distance from the lens to the image of the page is 12 cm, and the magnification of the image is -4.
We have to find out the distance from the lens to the image of the page and the magnification of the image.
(a) The distance from the lens to the image of the page:
As we know that the lens formula is `1/f = 1/v - 1/u` where;
f = focal length of the lens
v = distance of image from the lens
u = distance of object from the lens.
For a converging lens, the value of 'f' is taken as a positive (+) quantity.
Substituting the given values, we have;
f = +4 cm
v = ?
u = 3 cm
Hence, we have to find out the distance from the lens to the image of the page using the lens formula;[tex]1/4 = 1/v - 1/3= > 3v - 4v = -12= > v = +12/-1= > v = -12 cm[/tex]
The negative value of 'v' indicates that the image is formed on the same side of the lens as the object.
The distance from the lens to the image of the page is 12 cm.
(b) The magnification of the image: Magnification (m) is defined as the ratio of the height of the image (h') to the height of the object (h);
m = h'/h
We know that the formula of magnification is;
m = v/u
Substituting the given values, we get;
m = -12/3
= -4T
he magnification of the image is -4.
This indicates that the image is virtual, erect, and 4 times the size of the object.
As a result, the distance from the lens to the image of the page is 12 cm, and the magnification of the image is -4.
The magnifying glass forms a magnified, virtual, and erect image of the object at a position beyond its focal length.
The magnification of the image produced is directly proportional to the ratio of the focal length of the lens to the distance between the lens and the object.
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Given yı(t) = ? and y2(t) = t-1 satisfy the corresponding homogeneous equation of tły"? – 2y = - + + 2t4, t > 0 Then the general solution to the non-homogeneous equation can be written as y(t) = cıyı(t) + c2y2(t) + yp(t). Use variation of parameters to find yp(t). yp(t) = =
The required particular solution is given by : y(t) = c1y1(t) + c2y2(t) + yp(t)= c1 + c2(t - 1) + ln(2) - ln(t^4 + 1) + 3 ln(t) - 1/2 t^2 + 2t - 2 ln(t+1).
Given y1(t) = ? and y2(t) = t-1 satisfy the corresponding homogeneous equation of tły"? – 2y = - + + 2t4, t > 0.
Then, the general solution to the non-homogeneous equation can be written as y(t) = c1y1(t) + c2y2(t) + yp(t).
We have to use variation of parameters to find yp(t).
The variation of parameters formula states that
yp(t) = -y1(t) * ∫(y2(t) * r(t)) / (W(y1,y2))dt + y2(t) * ∫(y1(t) * r(t)) / (W(y1,y2))dt
Here, r(t) = (-3 + 2t^4) / t.
W(y1,y2) is the Wronskian which is given by
W(y1,y2) = |y1 y2|
= | 1 t-1|
= 1 + t
The two solutions of the corresponding homogeneous equation arey1(t) = 1 and y2(t) = t-1.
Now, we need to calculate the integrals
∫(y2(t) * r(t)) / (W(y1,y2))dt = ∫[(t - 1) * ((-3 + 2t^4) / t)] / (1 + t)dt
Let u = t^4 + 1, then
du = 4t^3 dt
⇒ dt = (1 / 4t^3) du
Substituting for dt, the integral becomes
∫[(t - 1) * ((-3 + 2t^4) / t)] / (1 + t)dt
= -1/2 ∫(u - 2) / (u) du
= -1/2 ∫(u / u) du + 1/2 ∫(2 / u) du
= -1/2 ln|u| + ln|u^2| + C
= ln|t^4 + 1| - ln(2) + 2 ln|t| + C1
where C1 is the constant of integration.
∫(y1(t) * r(t)) / (W(y1,y2))dt
= ∫(1 * (-3 + 2t^4) / (t(1 + t))) dt
= ∫(-3/t + 2t^3 - 2t^2 + 2t) / (1 + t) dt
= -3 ln|t| + 1/2 t^2 - 2t + 2 ln|t+1| + C2
where C2 is the constant of integration.
Using the above two integrals and the formula for yp(t), we have
yp(t) = -y1(t) * ∫(y2(t) * r(t)) / (W(y1,y2))dt + y2(t) * ∫(y1(t) * r(t)) / (W(y1,y2))dt
= -1 ∫[(t - 1) * ((-3 + 2t^4) / t)] / (1 + t)dt + (t - 1) ∫(1 * (-3 + 2t^4) / (t(1 + t))) dt
= ln(2) - ln(t^4 + 1) + 3 ln(t) - 1/2 t^2 + 2t - 2 ln(t+1)
Therefore, the particular solution of the non-homogeneous equation isyp(t) = ln(2) - ln(t^4 + 1) + 3 ln(t) - 1/2 t^2 + 2t - 2 ln(t+1).
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A candy company has 141 kg of chocolate covered nuts and 81 kg of chocolate-covered raisins to be sold as two different mixes One me will contain half nuts and halt raisins and will sel for $7 pet kg. The other mix will contun nuts and raisins and will sell ter so 50 per kg. Complete parts a, and b. 4 (a) How many kilograms of each mix should the company prepare for the maximum revenue? Find the maximum revenue The company should preparo kg of the test mix and kg of the second mix for a maximum revenue of s| (b) The company raises the price of the second mix to $11 per kg Now how many klograms of each ma should the company propare for the muomum revenue? Find the maximum revenue The company should prepare kg of the first mix and I kg of the second mix for a maximum revenue of
The maximum revenue is $987, and it occurs when the company produces 141 kg of the second mix and 0 kg of the first mix.
Corner point (0, 81): R = 7x + 5y = 7(0) + 5(81) = 405
Set up variables
Let x be the number of kilograms of the first mix (half nuts and half raisins) that the company produces. Let y be the number of kilograms of the second mix (nuts and raisins) that the company produces.
We want to maximize the revenue, which is the total amount of money earned by selling the mixes. So, we need to express the revenue in terms of x and y and then find the values of x and y that maximize the revenue.
Step 1: Rewrite the revenue function
The revenue from selling the first mix is still 7x dollars, but the revenue from selling the second mix is now 11y dollars (since it sells for $11 per kg).
Therefore, the total revenue is R = 7x + 11y dollars.
Step 2: Rewrite the constraints
The constraints are still the same: x/2 + y/2 ≤ 141 and x/2 + y/2 ≤ 81.
Step 3: Draw the feasible region
The feasible region is still the same, so we can use the same graph:Graph of the feasible region for the chocolate mix problem
Step 4: Find the corner points of the feasible region
The corner points are still the same: (0, 81), (141, 0), and (54, 54).
Step 5: Evaluate the revenue function at the corner points
Corner point (0, 81): R = 7x + 11y = 7(0) + 11(81) = 891
Corner point (141, 0): R = 7x + 11y = 7(141) + 11(0) = 987
Corner point (54, 54): R = 7x + 11y = 7(54) + 11(54) = 756
The maximum revenue is $987, and it still occurs when the company produces 141 kg of the second mix and 0 kg of the first mix.
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Let G be a finite group and p a prime.
(i)If P is an element of Syl_p(G) and H is a subgroup of G containing P,then prove that P is an element of Syl_p(H).
(ii)If H is a subgroup of G and Q is an element of Syl_p(H),then prove that gQg^-1 is an element of Syl_p(gHg^-1).
Let G be a finite group and p a prime. To prove that P is an element of Syl p(H) and to prove that P is an element of Syl p(H), the following method is followed.
(i)If P is an element of Syl p(G) and H is a subgroup of G containing P, then prove that P is an element of Syl p(H).
We know that, p-subgroup of G, which is of the largest order, is known as a Sylow p-subgroup of G. Also, the set of all Sylow p-subgroups of G is written as Sylp(G).By the third Sylow theorem, all the Sylow p-subgroups are conjugate to each other. That is, if P and Q are two Sylow p-subgroups of G, then there is a g ∈ G such that P = gQg⁻¹. Let P be an element of Sylp(G) and H be a subgroup of G containing P. Now we will prove that P is an element of Syl p(H).Now, the order of P in G is pⁿ, where n is the largest positive integer such that pⁿ divides the order of G. Similarly, the order of P in H is p^m, where m is the largest positive integer such that p^m divides the order of H. We know that, the order of H is a divisor of the order of G. Since P is a Sylow p-subgroup of G, n is the largest integer such that pⁿ divides the order of G. Thus pⁿ does not divide the order of H. That is, m < n. Thus the order of P in H is strictly less than the order of P in G. So P cannot be a Sylow p-subgroup of H. Hence, P is not a Sylow p-subgroup of H. Therefore, P is an element of Sylp(H).
(ii)To prove this we have assumed that H is a subgroup of G and P is a Sylow p-subgroup of G containing H. Therefore, we need to show that P is a Sylow p-subgroup of H. The order of P in G is pⁿ, where n is the largest positive integer such that pⁿ divides the order of G. Similarly, the order of P in H is p^m, where m is the largest positive integer such that p^m divides the order of H. We need to prove that P is the unique Sylow p-subgroup of H. For that, we need to show that if Q is any other Sylow p-subgroup of H, then there exists h ∈ H such that P = hQh⁻¹. Now, the order of Q in H is p^m, and since Q is a Sylow p-subgroup of H, m is the largest integer such that p^m divides the order of H. Since P is a Sylow p-subgroup of G, n is the largest integer such that pⁿ divides the order of G. We know that, the order of H is a divisor of the order of G. Therefore, m ≤ n. But P is a Sylow p-subgroup of G containing H, so P is a subgroup of G containing Q. Therefore, by the second Sylow theorem, there exists a g ∈ G such that Q = gPg⁻¹. Now, g is not necessarily in H, but we can consider the element hgh⁻¹, which is in H, since H is a subgroup of G. Also, hgh⁻¹P(hgh⁻¹)⁻¹ = hgPg⁻¹h⁻¹ = Q. Hence, P and Q are conjugate in H, and therefore, Q is also a Sylow p-subgroup of G. But P is a Sylow p-subgroup of G containing H. Hence, Q = P. Therefore, P is the unique Sylow p-subgroup of H.
Hence, we can conclude that if P is an element of Syl p(G) and H is a subgroup of G containing P, then P is an element of Syl p(H).Also, we can conclude that if H is a subgroup of G and Q is an element of Syl p(H), then gQg^-1 is an element of Syl p(gHg^-1).
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Let {Xn, n ≥ 1} be a sequence of i.i.d. Bernoulli random variables with parameter 1/2. Let X be a Bernoulli random variable taking the values 0 and 1 with probability each and let Y = 1-X. (a) Explain why Xn --> X and Xn --> Y. (b) Show that Xn --> Y, that is, Xn does not converge to Y in probability.
a) X is a Bernoulli random variable with parameter 1/2, it has the same expected value as Xn, i.e., E[X] = 1/2.
b) we have shown that Xn → Y in probability, which contradicts the conclusion we reached in part (a). Therefore, Xn does not converge to Y in probability.
(a) The sequence {Xn, n ≥ 1} consists of i.i.d. Bernoulli random variables with parameter 1/2.
Hence, The expected value of each Xn is:
E[Xn] = 0(1/2) + 1(1/2) = 1/2
By the Law of Large Numbers, as n approaches infinity, the sample mean of the sequence, which is the average of the Xn values from X1 to Xn, converges to the expected value of the sequence.
Therefore, we have:
Xn → E[Xn] = 1/2 as n → ∞
Since X is a Bernoulli random variable with parameter 1/2, it has the same expected value as Xn, i.e., E[X] = 1/2.
Therefore, using the same argument as above, we have:
Xn → X as n → ∞
Similarly, Y = 1 - X is also a Bernoulli random variable with parameter 1/2, and therefore, it also has an expected value of 1/2.
Hence:
Xn → Y as n → ∞
(b) To show that Xn does not converge to Y in probability, we need to find the limit of the probability that |Xn - Y| > ε as n → ∞ for some ε > 0. Since Xn and Y are both Bernoulli random variables with parameter 1/2, their distributions are symmetric and take on values of 0 and 1 only.
This means that:
|Xn - Y| = |Xn - (1 - Xn)| = 1
Therefore, for any ε < 1, we have:
P(|Xn - Y| > ε) = P(|Xn - Y| > 1) = 0
This means that the probability of |Xn - Y| being greater than any positive constant is zero, which implies that Xn converges to Y in probability.
Hence, we have shown that Xn → Y in probability, which contradicts the conclusion we reached in part (a). Therefore, Xn does not converge to Y in probability.
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Tutorial Exercise 3 Given that ex dx = e3-e, use this result to evaluate 2ex + 7 dx. Step 1 Using laws of exponents, we have e7ee4e-2X Submit Skip (you cannot come back)
The value of ∫2ex + 7 dx is 2(e3-e) + 7x + C.
∫2e3 x e-x + 7 dx= 2∫e3 x e-x dx + 7 ∫dx= 2(e3-e) + 7x + C,
where C is the constant of integration.
The value of ∫2ex + 7 dx is 2(e3-e) + 7x + C.
The given problem is asking us to evaluate the integral of 2ex + 7 dx.
Let's solve the problem step by step:
Step 1: We have to use the given result to evaluate the integral.
Using the laws of exponents we can write:
ex dx = e3-e
⇒ ex dx = e3 x e-x dx.
Step 2: Now let's substitute the above result in our given problem
2ex + 7 dx= 2(e3 x e-x) + 7 dx
= 2e3 x e-x + 7 dx.
Step 3: Now, we can integrate the above expression using the power rule of integration.
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Suppose H is a 3 x 3 matrix with entries hij. In terms of det (H
We can also use the following formula for matrices larger than 3 x 3:det(A) = a11A11 + a12A12 + … + a1nA1nwhere A11, A12, A1n are the cofactors of the first row.
Suppose H is a 3 x 3 matrix with entries hij. In terms of det (H), we can write that the determinant of matrix H is represented by the following equation:
det(H)
= h11(h22h33 − h23h32) − h12(h21h33 − h23h31) + h13(h21h32 − h22h31)
Therefore, we can say that det(H) is expressed as a sum of products of three elements from matrix H.
It can also be said that the determinant of a matrix is a scalar value that can be used to describe the linear transformation between two-dimensional spaces.
To calculate the determinant of a 3 x 3 matrix, we use the formula above.
We can also use the following formula for matrices larger than 3 x 3:det(A) = a11A11 + a12A12 + … + a1nA1nwhere A11, A12, A1n are the cofactors of the first row.
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A broad class of second order linear homogeneous differential equations can, with some manip- ulation, be put into the form (Sturm-Liouville) (P(x)u')' +9(x)u = \w(x)u Assume that the functions p, q, and w are real, and use manipulations much like those that led to the identity Eq. (5.15). Derive the analogous identity for this new differential equation. When you use separation of variables on equations involving the Laplacian you will commonly come to an ordinary differential equation of exactly this form. The precise details will depend on the coordinate system you are using as well as other aspects of the PDE. cb // L'dir = nudim - down.' = waz-C + draai u – uz dx uyu ԴԱ dx dx u'un Put this back into the Eq. (5.14) and the integral terms cancel, leaving b ob ut us – 2,037 = (1, - o) i dx uru1 (5.15) a
Sturm-Liouville, a broad class of second-order linear homogeneous differential equations, can be manipulated into the form (P(x)u')' +9(x)u = w(x)u. The analogous identity for this differential equation can be derived by using manipulations similar to those that led to the identity equation (5.15). The functions p, q, and w are real.
When separation of variables is used on equations that include the Laplacian, an ordinary differential equation of exactly this form is commonly obtained. The specific details will be determined by the coordinate system as well as other aspects of the PDE. The identity equation (5.15) can be written as follows:∫ a to b [(p(x)(u'(x))^2 + q(x)u(x)^2] dx = ∫ a to b [u(x)^2(w(x)-λ)/p(x)] dx where λ is an arbitrary constant and u(x) is a function. The differential equation can be put into the form (Sturm-Liouville): (P(x)u')' + 9(x)u = w(x)u.
Assume that the functions p, q, and w are real, and use manipulations much like those that led to the identity Eq. (5.15). Derive the analogous identity for this new differential equation. When you use separation of variables on equations involving the Laplacian you will commonly come to an ordinary differential equation of exactly this form. The precise details will depend on the coordinate system you are using as well as other aspects of the PDE.
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Find the volume under the surface z = 3x² + y², on the triangle with vertices (0,0), (0, 2) and (4,2).
To find the volume under the surface z = 3x² + y² over the given triangle, we can integrate the function over the triangular region in the xy-plane.
The vertices of the triangle are (0,0), (0,2), and (4,2). The base of the triangle lies along the x-axis from x = 0 to x = 4, and the height of the triangle is from y = 0 to y = 2.
Using a double integral, the volume V under the surface is given by:
V = ∫∫R (3x² + y²) dA
where R represents the triangular region in the xy-plane.
Integrating with respect to y first, we have:
V = ∫[0,4] ∫[0,2] (3x² + y²) dy dx
Integrating with respect to y, we get:
V = ∫[0,4] [(3x²)y + (y³/3)]|[0,2] dx
Simplifying the integral, we have:
V = ∫[0,4] (6x² + 8/3) dx
Evaluating the integral, we get:
V = [2x³ + (8/3)x] |[0,4]
V = 128/3
Therefore, the volume under the surface z = 3x² + y² over the given triangle is 128/3 cubic units.
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Consider the differential equation xy" + ay = 0 (a) Show that x = 0 is an irregular singular point of (3). 1 (b) Show that substitution t = -yields the differential equation X d² y 2 dy + dt² t dt + ay = 0 (c) Show that t = 0 is a regular singular point of the equation in part (b) (d) Find two power series solutions of the differential equation in part (b) about t = 0. (e) Express a general solution of the original equation (3) in terms of elementary function, i.e, not in the form of power series. (3)
The value of p is zero and y is an irregular point for the differential equation.
(a) We know that the differential equation is of the form,xy" + ay = 0
For this differential equation, we have to check the values of p and q as given below:
p = lim[x→0] [(0)(xq)]/x = 0
The value of p is zero, therefore, x = 0 is a singular point.
The value of q can be calculated by substituting y = (x^r) in the given equation and finding the values of r such that y ≠ 0.
The calculation is shown below:
xy" + ay = 0
Differentiating w.r.t. x,y' + xy" = 0
Differentiating again w.r.t. x,y" + 2y' = 0
Substituting y = (x^r) in the above equation:
(x^r) [(r)(r - 1)(x^(r - 2)) + 2(r)(x^(r - 1))] + a(x^r) = 0
On dividing by (x^r), we get(r)(r - 1) + 2(r) + a = 0(r² + r + a) = 0
Therefore, the roots are given by,r = [-1 ± √(1 - 4a)]/2
Now, the value of q will be given by,
q = min{0, 1 - (-1 + √(1 - 4a))/2, 1 - (-1 - √(1 - 4a))/2}= min{0, (1 + √(1 - 4a))/2, (1 - √(1 - 4a))/2}
The value of q is negative and the roots are complex.
Hence x = 0 is an irregular singular point of the differential equation.
(b) On substituting t = -y in the differential equation xy" + ay = 0, we get
x(d²y/dt²) - (dy/dt) + ay = 0
Differentiating w.r.t. t, we get
x(d³y/dt³) - d²y/dt² + a(dy/dt) = 0
(c) The differential equation obtained in part (b) is
x(d²y/dt²) - (dy/dt) + ay = 0
The coefficients of the differential equation are analytic at t = 0.
The differential equation has a regular singular point at t = 0.
(d) Let the power series solution of the differential equation in part (b) be of the form,
y = a₀ + a₁t + a₂t² + a₃t³ + ....
Substituting this in the differential equation, we get,
a₀x + a₂(x + 2a₀) + a₄(x + 2a₂ + 6a₀) + ...= 0a₀ = 0a₂ = 0a₄ = -a₀/3 = 0a₆ = -a₂/5 = 0
Therefore, the first two power series solutions of the differential equation are given by,y₁ = a₁ty₂ = a₃t³
(e) We have the differential equation,xy" + ay = 0
This differential equation is of the form of Euler's differential equation and the power series solution is given by,
y = x^(m) ∑[n≥0] [an(x)ⁿ]
The power series solution is of the form,y = x^(m) [c₀ + c₁(-a/x)^(1 - m) + c₂(-a/x)^(2 - m) + ...]
On substituting this power series in the given differential equation, we get,∑[n≥0] [an(-1)ⁿ(n^2 - nm + a)]= 0
Therefore, the value of m is given by the roots of the characteristic equation,m(m - 1) + a = 0
The roots are given by,m = (1 ± √(1 - 4a))/2
The power series solution can be expressed in terms of elementary functions as shown below:
y = cx^(1 - m) [C₁ Jv(2√ax^(1 - m)/√(1 - 4a)) + C₂ Yv(2√ax^(1 - m)/√(1 - 4a))]
where Jv(x) and Yv(x) are Bessel functions of the first and second kind, respectively, of order v.
The constants C₁ and C₂ are determined by the boundary conditions.
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i) a) Prove that the given function u(x,y) = -8x3y + 8xy3 is harmonic b) Find y, the conjugate harmonic function and write f(z). ii) Evaluate Sc (y + x - 4ix)dz where c is represented by: C:The straight line from Z = 0 to Z = 1+i Cz: Along the imiginary axis from Z = 0 to Z = i.
i)a) The function u(x,y) is harmonic. ; b) f(z) = 4x^4 + 8x³i + 4y^4 - 12xy²+ 8y³i ; ii) The result is: Sc (y + x - 4ix)dz = 5i + (y + x - 4 - 4i) (1 + i).
Let's solve the given problem step by step below.
i) a) To show that a function is harmonic, we need to prove that it satisfies the Laplace's equation.
Thus, we can write u(x,y) = -8x3y + 8xy3 in terms of x and y as follows:
u(x,y) = -8x^3y + 8xy^3
∴ ∂u/∂x = -24x^2y + 8y^3 ----(i)
∴ ∂²u/∂x² = -48xy ----(ii)
Similarly, we can find the partial derivatives with respect to y:
∴ ∂u/∂y = -8x^3 + 24xy² ----(iii)
∴ ∂²u/∂y² = 48xy ----(iv)
Therefore, by adding (ii) and (iv), we get
:∂²u/∂x² + ∂²u/∂y² = 0
So, the function u(x,y) is harmonic.
b) We know that if a function u(x,y) is harmonic, then the conjugate harmonic function y(x,y) can be found as:
y(x,y) = ∫∂u/∂x dy - ∫∂u/∂y dx + c
where c is a constant of integration.
Here,
∂u/∂x = -24x^2y + 8y^3
∂u/∂y = -8x^3 + 24xy²
∴ ∫∂u/∂x dy = -12x²y² + 4y^4 + d1(y)
∴ ∫∂u/∂y dx = -4x^4 + 12x²y² + d2(x)
where d1(y) and d2(x) are constants of integration.
To get the value of c, we can equate both the integrals:
d1(y) = -4x^4 + 12x²y² + c
Therefore,
y(x,y) = -12x²y² + 4y^4 - 4x^4 + 12x²y² + c
= 4y^4 - 4x^4 + c
Now, we can find f(z) using the Cauchy-Riemann equations:
∴ u_x = -24x^2y + 8y^3
= v_y
∴ u_y = -8x^3 + 24xy²
= -v_x
Thus,
f'(z) = u_x + iv_x
= -24x^2y + 8y^3 - i(8x^3 - 24xy²)
= (8y^3 + 24xy²) - i(8x^3 + 24xy²)
Therefore,
f(z) = ∫f'(z) dz
= ∫[(8y^3 + 24xy²) - i(8x^3 + 24xy²)] dz
= 4x^4 + 8x³i + 4y^4 + 8y³i - 12xy²i²
= 4x^4 + 8x³i + 4y^4 - 12xy²+ 8y³i
Let's evaluate Sc (y + x - 4ix)dz where c is represented by:
C: The straight line from Z = 0 to Z = 1+i C
z: Along the imaginary axis from Z = 0 to Z = i.
Given,
Sc (y + x - 4ix)dz
= [(y + x - 4ix) (i)] (i - 0) + [(y + x - 4ix) (1 + i)] (0 - i)
= 5i + (y + x) (1 + i) - 4i (1 + i)
= 5i + (y + x - 4 - 4i) (1 + i)
Thus, the result is:
Sc (y + x - 4ix)dz
= 5i + (y + x - 4 - 4i) (1 + i).
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In a real estate company the management required to know the recent range of rent paid in the capital governorate, assuming rent follows a normal distribution. According to a previous published research the mean of rent in the capital was BD 568, with a standard deviation of 105
The real estate company selected a sample of 199 and found that the mean rent was BD684
Calculate the test statistic. (write your answer to 2 decimal places, )
The test statistic is approximately equal to 3.50.
Test statistics are numerical values calculated in statistical hypothesis testing to determine the likelihood of observing a certain result under a specific hypothesis. They provide a standardized measure of the discrepancy between the observed data and the expected values.
To calculate the test statistic, we can use the formula for the z-score:
z = (x - μ) / (σ / √(n))
Where:
x = Sample mean
μ = Population mean
σ = Population standard deviation
n = Sample size
Given:
x = BD 684
μ = BD 568
σ = 105
n = 199
Plugging these values into the formula:
z = (684 - 568) / (105 / sqrt(199))
Calculating the value:
z ≈ 3.50
Therefore, the test statistic is approximately 3.50.
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