Answer
nghiệmTrảingu từng bước:
Use the elimination method to solve this system. − 4 x − 2 y = − 12, 4 x + 8 y = − 24
Answer:
x = 6; y = -6
Step-by-step explanation:
-4x - 2y = -12
4x + 8y = -24
Add the two equations, so x is eliminated:
6y = -36
6y/6 = -36/6
y = -6
Plug in y, to solve for x
-4x - 2y = -12
-4x - 2(-6) = -12
-4x +12 = -12
-4x = -12 -12
-4x = -24
-4x/-4 = -24/-4
x = 6
Answer from Gauthmath
help with 1 b please. using ln.
Answer:
[tex]\displaystyle \frac{dy}{dx} = \frac{1}{(x - 2)^2\sqrt{\frac{x}{2 - x}}}[/tex]
General Formulas and Concepts:
Pre-Algebra
Equality PropertiesAlgebra I
Terms/CoefficientsFactoringExponential Rule [Root Rewrite]: [tex]\displaystyle \sqrt[n]{x} = x^{\frac{1}{n}}[/tex]Algebra II
Natural logarithms ln and Euler's number eLogarithmic Property [Exponential]: [tex]\displaystyle log(a^b) = b \cdot log(a)[/tex]Calculus
Differentiation
DerivativesDerivative NotationImplicit DifferentiationDerivative Property [Multiplied Constant]: [tex]\displaystyle \frac{d}{dx} [cf(x)] = c \cdot f'(x)[/tex]
Derivative Property [Addition/Subtraction]: [tex]\displaystyle \frac{d}{dx}[f(x) + g(x)] = \frac{d}{dx}[f(x)] + \frac{d}{dx}[g(x)][/tex]
Basic Power Rule:
f(x) = cxⁿf’(x) = c·nxⁿ⁻¹Derivative Rule [Quotient Rule]: [tex]\displaystyle \frac{d}{dx} [\frac{f(x)}{g(x)} ]=\frac{g(x)f'(x)-g'(x)f(x)}{g^2(x)}[/tex]
Derivative Rule [Chain Rule]: [tex]\displaystyle \frac{d}{dx}[f(g(x))] =f'(g(x)) \cdot g'(x)[/tex]
Step-by-step explanation:
*Note:
You can simply just use the Quotient and Chain Rule to find the derivative instead of using ln.
Step 1: Define
Identify
[tex]\displaystyle y = \sqrt{\frac{x}{2 - x}}[/tex]
Step 2: Rewrite
[Function] Exponential Rule [Root Rewrite]: [tex]\displaystyle y = \bigg( \frac{x}{2 - x} \bigg)^\bigg{\frac{1}{2}}[/tex][Equality Property] ln both sides: [tex]\displaystyle lny = ln \bigg[ \bigg( \frac{x}{2 - x} \bigg)^\bigg{\frac{1}{2}} \bigg][/tex]Logarithmic Property [Exponential]: [tex]\displaystyle lny = \frac{1}{2}ln \bigg( \frac{x}{2 - x} \bigg)[/tex]Step 3: Differentiate
Implicit Differentiation: [tex]\displaystyle \frac{dy}{dx}[lny] = \frac{dy}{dx} \bigg[ \frac{1}{2}ln \bigg( \frac{x}{2 - x} \bigg) \bigg][/tex]Logarithmic Differentiation [Derivative Rule - Chain Rule]: [tex]\displaystyle \frac{1}{y} \ \frac{dy}{dx} = \frac{1}{2} \bigg( \frac{1}{\frac{x}{2 - x}} \bigg) \frac{dy}{dx} \bigg[ \frac{x}{2 - x} \bigg][/tex]Chain Rule [Basic Power Rule]: [tex]\displaystyle \frac{1}{y} \ \frac{dy}{dx} = \frac{1}{2} \bigg( \frac{1}{\frac{x}{2 - x}} \bigg) \bigg[ \frac{2}{(x - 2)^2} \bigg][/tex]Simplify: [tex]\displaystyle \frac{1}{y} \ \frac{dy}{dx} = \frac{-1}{x(x - 2)}[/tex]Isolate [tex]\displaystyle \frac{dy}{dx}[/tex]: [tex]\displaystyle \frac{dy}{dx} = \frac{-y}{x(x - 2)}[/tex]Substitute in y [Derivative]: [tex]\displaystyle \frac{dy}{dx} = \frac{-\sqrt{\frac{x}{2 - x}}}{x(x - 2)}[/tex]Rationalize: [tex]\displaystyle \frac{dy}{dx} = \frac{-\frac{x}{2 - x}}{x(x - 2)\sqrt{\frac{x}{2 - x}}}[/tex]Rewrite: [tex]\displaystyle \frac{dy}{dx} = \frac{-x}{x(x - 2)(2 - x)\sqrt{\frac{x}{2 - x}}}[/tex]Factor: [tex]\displaystyle \frac{dy}{dx} = \frac{-x}{-x(x - 2)^2\sqrt{\frac{x}{2 - x}}}[/tex]Simplify: [tex]\displaystyle \frac{dy}{dx} = \frac{1}{(x - 2)^2\sqrt{\frac{x}{2 - x}}}[/tex]Topic: AP Calculus AB/BC (Calculus I/I + II)
Unit: Differentiation
Book: College Calculus 10e
sin4x.sin5x+sin4x.sin3x-sin2x.sinx=0
Recall the angle sum identity for cosine:
cos(x + y) = cos(x) cos(y) - sin(x) sin(y)
cos(x - y) = cos(x) cos(y) + sin(x) sin(y)
==> sin(x) sin(y) = 1/2 (cos(x - y) - cos(x + y))
Then rewrite the equation as
sin(4x) sin(5x) + sin(4x) sin(3x) - sin(2x) sin(x) = 0
1/2 (cos(-x) - cos(9x)) + 1/2 (cos(x) - cos(7x)) - 1/2 (cos(x) - cos(3x)) = 0
1/2 (cos(9x) - cos(x)) + 1/2 (cos(7x) - cos(3x)) = 0
sin(5x) sin(-4x) + sin(5x) sin(-2x) = 0
-sin(5x) (sin(4x) + sin(2x)) = 0
sin(5x) (sin(4x) + sin(2x)) = 0
Recall the double angle identity for sine:
sin(2x) = 2 sin(x) cos(x)
Rewrite the equation again as
sin(5x) (2 sin(2x) cos(2x) + sin(2x)) = 0
sin(5x) sin(2x) (2 cos(2x) + 1) = 0
sin(5x) = 0 or sin(2x) = 0 or 2 cos(2x) + 1 = 0
sin(5x) = 0 or sin(2x) = 0 or cos(2x) = -1/2
sin(5x) = 0 ==> 5x = arcsin(0) + 2nπ or 5x = arcsin(0) + π + 2nπ
… … … … … ==> 5x = 2nπ or 5x = (2n + 1)π
… … … … … ==> x = 2nπ/5 or x = (2n + 1)π/5
sin(2x) = 0 ==> 2x = arcsin(0) + 2nπ or 2x = arcsin(0) + π + 2nπ
… … … … … ==> 2x = 2nπ or 2x = (2n + 1)π
… … … … … ==> x = nπ or x = (2n + 1)π/2
cos(2x) = -1/2 ==> 2x = arccos(-1/2) + 2nπ or 2x = -arccos(-1/2) + 2nπ
… … … … … … ==> 2x = 2π/3 + 2nπ or 2x = -2π/3 + 2nπ
… … … … … … ==> x = π/3 + nπ or x = -π/3 + nπ
(where n is any integer)
A rectangle has a perimeter equal to 24 if we consider its width x how could we talk about its length y in terms of x what are the possible values of x what aree the possible values of y
2x + 2y must equal 24. 24 - 2x = 2y and 24 - 2y = 2x. Therefore, 12 - y = x. x could be able to add with y to get 12.
example: x = 4, y = 8. (4 + 4 + 8 + 8 = 16 + 8 = 24)
x = 9, y = 3. (9 + 9 + 3 + 3 = 24)
x = 5, y = 7. (5 + 5 + 7 + 7 = 24)
Hey guys can help me please
Answer:
Can you select multiple answers to this question? then option A, B and C all three applies, if only one the go for option C, since that's the major change happens to the parent function
Three different classes contain 20, 18, and 25 students, respectively, and no student is a member of more than one class. If a team is to be composed of one student from each of these three classes, in how many different ways can the members of the team be chosen?
Answer:
9000
Step-by-step explanation:
20 x 18 x 25
20 options for one member
18 options for another member
25 members for the last member
A bag contains 35 marbles, 11 of which are red. A marble is randomly selected from the bag, and it is blue. This blue marble is NOT placed back in the bag. A second marble is randomly drawn from the bag. Find the probability that this second marble is NOT red.
Answer:
11 red + 24 blue = 35 marbles
If 1 blue is withdrawn
11 red + 23 blue = 34 marbles
P = 23 / 34 = .38 probability of drawing blue marble
Joey's strategy for his first marathon (26.2 miles)was to run 2 miles, walk 1 mile, run 2 miles, walk 1 mile, and continue this pattern until he completed the race. Joey's average running pace is 8 minutes per mile, and his average walking pace is 16 minutes per mile. How many minutes will it take Joey to complete the marathon
========================================================
Explanation:
We have this sequence
(2+1)+(2+1)+(2+1)...
Effectively, we're repeating "2+1" over and over.
We can see that
2+1 = 3(2+1)+(2+1) = 3+3 = 6(2+1)+(2+1)+(2+1) = 3+3+3 = 9Each time we add on another copy of (2+1), we're adding on 3
Dividing 26.2 over 3 gets us (26.2)/3 = 8.733 approximately
If we had 8 copies of (2+1) added together, then we would get
8*(2+1) = 8*3 = 24
This is 26.2-24 = 2.2 miles short of his goal.
He'll need to run 2 more miles, plus walk another 0.2 of a mile
----------------------------------------------------
In summary so far, Joey will run 8+1 = 9 sections (two miles each) and walk 8 sections that are 1 mile each. At the very end, he'll walk 0.2 miles to finish the race. Each running and walking section is alternated of course.
Since he runs 9 sections, each 2 miles, that accounts for 9*2 = 18 miles.
His running pace is 8 minutes per mile, so this means he has run for 8*18 = 144 minutes. This is just the running part and not the walking part.
Let A = 144 so we can use it later.
----------------------------------------------------
He walks 8 sections of 1 mile each. His walking pace is 16 minutes per mile. This must mean he spends 8*16 = 128 minutes on this walking portion.
Then for the last 0.2 mile section he walks, we can solve the proportion below
(1 mile)/(16 min) = (0.2 miles)/(x min)
1/16 = 0.2/x
1*x = 16*0.2
x = 3.2
He spends 3.2 minutes walking the remaining 0.2 of a mile at the end.
So his total walking time is 128+3.2 = 131.2 minutes.
Let B = 131.2
-----------------------------------------------------
To wrap things up, we'll add up the results of each of the previous two sections.
A = total running time = 144 min
B = total walking time = 131.2 min
C = total marathon time
C = A+B
C = 144+131.2
C = 275.2 minutes
This converts to 275 min, 12 sec.
This is also equivalent to 4 hrs, 35 min, 12 sec.
Find the missing length. The triangles are similar.
Answer:
Missing length = 12
Step-by-step explanation:
Let x represent the missing length.
Since the triangles are similar, ∆KLM ~ ∆KRS, therefore, the ratio of their corresponding side lengths would be the same. This implies that:
KL/KR = KM/KS
KL = 65
KR = 65 - 52
KR = 13
KM = 60
KS = x
Plug in the values
65/13 = 60/x
Cross multiply
65*x = 60*13
65x = 780
Divide both sides by 65
65x/65 = 780/65
x = 12
People were asked if they owned an artificial Christmas tree. Of 78 people who lived in an apartment, 38 own an artificial Christmas tree. Also it was learned that of 84 people who own their home, 46 own an artificial Christmas tree. Is there a significant difference in the proportion of apartment dwellers and home owners who own artificial Christmas trees
Answer:
The p-value of the test is 0.4414, higher than the standard significance level of 0.05, which means that there is not a a significant difference in the proportion of apartment dwellers and home owners who own artificial Christmas trees.
Step-by-step explanation:
Before testing the hypothesis, we need to understand the central limit theorem and subtraction of normal variables.
Central Limit Theorem
The Central Limit Theorem establishes that, for a normally distributed random variable X, with mean [tex]\mu[/tex] and standard deviation [tex]\sigma[/tex], the sampling distribution of the sample means with size n can be approximated to a normal distribution with mean [tex]\mu[/tex] and standard deviation [tex]s = \frac{\sigma}{\sqrt{n}}[/tex].
For a skewed variable, the Central Limit Theorem can also be applied, as long as n is at least 30.
For a proportion p in a sample of size n, the sampling distribution of the sample proportion will be approximately normal with mean [tex]\mu = p[/tex] and standard deviation [tex]s = \sqrt{\frac{p(1-p)}{n}}[/tex]
Subtraction between normal variables:
When two normal variables are subtracted, the mean is the difference of the means, while the standard deviation is the square root of the sum of the variances.
Apartment:
38 out of 78, so:
[tex]p_A = \frac{38}{78} = 0.4872[/tex]
[tex]s_A = \sqrt{\frac{0.4872*0.5128}{78}} = 0.0566[/tex]
Home:
46 out of 84, so:
[tex]p_H = \frac{46}{84} = 0.5476[/tex]
[tex]s_H = \sqrt{\frac{0.5476*0.4524}{84}} = 0.0543[/tex]
Test if the there a significant difference in the proportion of apartment dwellers and home owners who own artificial Christmas trees:
At the null hypothesis, we test if there is no difference, that is, the subtraction of the proportions is equal to 0, so:
[tex]H_0: p_A - p_H = 0[/tex]
At the alternative hypothesis, we test if there is a difference, that is, the subtraction of the proportions is different of 0, so:
[tex]H_1: p_A - p_H \neq 0[/tex]
The test statistic is:
[tex]z = \frac{X - \mu}{s}[/tex]
In which X is the sample mean, [tex]\mu[/tex] is the value tested at the null hypothesis, and s is the standard error.
0 is tested at the null hypothesis:
This means that [tex]\mu = 0[/tex]
From the samples:
[tex]X = p_A - p_H = 0.4872 - 0.5476 = -0.0604[/tex]
[tex]s = \sqrt{s_A^2 + s_H^2} = \sqrt{0.0566^2 + 0.0543^2} = 0.0784[/tex]
Value of the test statistic:
[tex]z = \frac{X - \mu}{s}[/tex]
[tex]z = \frac{-0.0604 - 0}{0.0784}[/tex]
[tex]z = -0.77[/tex]
P-value of the test and decision:
The p-value of the test is the probability of the difference being of at least 0.0604, to either side, plus or minus, which is P(|z| > 0.77), given by 2 multiplied by the p-value of z = -0.77.
Looking at the z-table, z = -0.77 has a p-value of 0.2207.
2*0.2207 = 0.4414
The p-value of the test is 0.4414, higher than the standard significance level of 0.05, which means that there is not a a significant difference in the proportion of apartment dwellers and home owners who own artificial Christmas trees.
Helen’s father’s car can travel an average of 18.5 miles on 1 gallon of gasoline. Gas at the local station costs $3.79 per gallon.
a) Helen’s mom took the car to the gas station and hand the cashier a $10 bill. How much gas could she buy? Round your answer to the nearest hundredth of a gallon.
9514 1404 393
Answer:
2.64 gallons
Step-by-step explanation:
Each gallon costs $3.79, so the number of gallons that can be bought with $10 is ...
$10/($3.79/gal) = (10/3.79) gal ≈ 2.6385 gal ≈ 2.64 gallons
The point A(−8,−4) is reflected over the origin and its image is point B. What are the coordinates of point b?
9514 1404 393
Answer:
B(8, 4)
Step-by-step explanation:
Reflection across the origin negates both coordinate values.
(x, y) ⇒ (-x, -y) . . . . . reflection across the origin
A(-8, -4) ⇒ B(8, 4)
Write the number 16,107,320 expanded form.
Answer:
Sixteen million, one hundred and seven thousand, three hundred twenty
Step-by-step explanation:
Would a scatter plot of the data described below be likely to show a positive relationship, negative relationship, or no relationship.
The number of letters in a person's first name and their heigh
There would likely be no relationship between first name and height of a person in a random sample.
Hope this helps :)
Answer: it’s B. I answered it right now and it said it was correct.
Step-by-step explanation:
McDonald’s fry’s are better than jack in the box’s fry’s.
Find the equation of the line passing through the point (1, -5)
and perpendicular to y 1x + 2
Answer:
-8 and 3
Step-by-step explanation:
The slope of the line will be - 8, the equation is y=-8x+3
I NEED HELP PLEASE!!
sine --> cosecant
csc(x) = 1/sin(x)
cosine --> secant
sec(x) = 1/cos(x)
tangent --> cotangent
cot(x) = 1/tan(x)
Correct Answer: A
Hope this helps!
Temperatures in northern Canada ranged as high as 37°F one summer. That same year the lowest temperature was −28°F. What was the range of temperatures for the year?
Answer:
65 degrees
Step-by-step explanation:
Find the range of temperatures by finding the difference between the lowest and highest temperatures:
37 - (-28)
37 + 28
= 65
So, the range of temperatures was 65 degrees
Carlos owns a small business. There was a profit of $9 on Saturday and a loss of $6 on Sunday. Find the total profit or loss for the weekend. $15 profit $3 loss $3 profit $15 loss
Answer:
$3 profit
Step-by-step explanation:
Since you got a profit of $9 on Saturday and a loss of $6 on Sunday, you have to subtract 9 and 6, which is 3.
Help with This question please
Answer:
A
Step-by-step explanation:
at a local college, four sections of economics are taught during the day and two sections are taught at night. 85 percent of the day sections are taught by full-time faculty. 30 percent of the evening sections are taught by full-time faculty. if jane has a part-time teacher for her economics course, what is the probability that she is taking a night class
Answer:
Hence The probability that she is taking a night class given that Jane has a part-time teacher = P(jane has a part-time teacher and she is taking night class )/P(jane has a part-time teacher) = 0.6999.
Step-by-step explanation:
Probability(full-time teacher/ day ) = 0.85
Probability(part-time teacher/ day ) = 1- 0.85 = 0.15
Probability(full-time teacher/ night) = 0.30
Probability(part-time teacher/ night) = 1 - 0.30 = 0.70
total no of section = 4+2 = 6
P(jane has part time teacher) = P(jane is from day section)*Probability(part-time teacher/ day )+P(jane is from night section)*Probability(part-time teacher/ night)
= (4/6)(0.15)+(2/6)(0.70) = 0.33
P(jane has part time teacher and she is taking night class ) = P(jane is from night section)*Probability(part-time teacher/ night) = (2/6)(0.70) = 0.23
According to Bayes theorem :
The probability that she is taking a night class given that Jane has a part-time teacher = P(jane has a part-time teacher and she is taking night class )/P(jane has a part-time teacher)
= 0.23/0.33
= 0.6999
3. Find the value of x in this figure
answer:
120°
Step-by-step explanation:
∠OPM=∠ONM=90°
X°＝360°-60°-90°*2＝120°
Base conversion. Perform the following conversion
675_10= ?___6
Answer:
3043 (base 6)
Step-by-step explanation:
216 36 6 1
3 0 4 3
216* 3 = 648
6*4 = 24
1*3 = 3
648+24+3 = 675
The weight of potato chip bags filled by a machine at a packaging plant is normally distributed, with a mean of 15.0 ounces and a standard deviation of 0.2 ounces. What is the probability that a randomly chosen bag will weigh more than 15.6 ounces
Answer:
0.0013 = 0.13% probability that a randomly chosen bag will weigh more than 15.6 ounces.
Step-by-step explanation:
Normal Probability Distribution
Problems of normal distributions can be solved using the z-score formula.
In a set with mean [tex]\mu[/tex] and standard deviation [tex]\sigma[/tex], the z-score of a measure X is given by:
[tex]Z = \frac{X - \mu}{\sigma}[/tex]
The Z-score measures how many standard deviations the measure is from the mean. After finding the Z-score, we look at the z-score table and find the p-value associated with this z-score. This p-value is the probability that the value of the measure is smaller than X, that is, the percentile of X. Subtracting 1 by the p-value, we get the probability that the value of the measure is greater than X.
Mean of 15.0 ounces and a standard deviation of 0.2 ounces.
This means that [tex]\mu = 15, \sigma = 0.2[/tex]
What is the probability that a randomly chosen bag will weigh more than 15.6 ounces?
This is 1 subtracted by the p-value of Z when X = 15.6. So
[tex]Z = \frac{X - \mu}{\sigma}[/tex]
[tex]Z = \frac{15.6 - 15}{0.2}[/tex]
[tex]Z = 3[/tex]
[tex]Z = 3[/tex] has a p-value of 0.9987.
1 - 0.9987 = 0.0013
0.0013 = 0.13% probability that a randomly chosen bag will weigh more than 15.6 ounces.
How many solutions does the nonlinear system of equations graphed below have?
A. Four
B. Two
C. One
D. Zero
Answer:
Option (A)
Step-by-step explanation:
Solution of two functions represented by the graph are the common points or point of intersection of the graphs.
From the graph attached,
Parabola and ellipse are intersecting each other at four points.
Therefore, solutions of the given non linear functions will be FOUR.
Option (A) will be the correct option.
How much does college tuition cost? That depends, of course, on where you go to college. Construct a weighted average. Using the data from "College Affordable for Most," estimate midpoints for the cost intervals. Say 46% of tuitions cost about $4,500; 21% cost about $7,500; 7% cost about $12,000; 8% cost about $18,000; 9% cost about $24,000; and 9% cost about $31,000. Compute the weighted average of college tuition charged at all colleges.
Answer:
0.127
Step-by-step explanation:
find the sum of the given infinite geometric series. NO LINKS OR ANSWERING QUESTIONS YOU DON'T KNOW
Answer:
320/3
Step-by-step explanation:
First find the common ratio
20/80 = 1/4
The sum of an infinite geometric series
sum = a1/ (1-r) where a1 is the first term and r is the common ratio
=80/ ( 1-1/4)
= 80/(3/4)
= 80 *4/3
= 320/3
A. Use the appropriate formula to determine the periodic deposit.
B. How much of the financial goal comes from deposits and how much comes from interest?
Periodic Deposit: $? at the end of each year
Rate: 7% compounded annually
Time: 18 years
Financial Goal: $130,000
The periodic deposit is? $
Answer:
A. Periodic deposit:
The goal is to make $130,000 by depositing a set amount every year.
This set amount is an annuity. The $130,000 is therefore the future value of the annuity after 18 years.
Future value of annuity = Annuity * Future value of annuity factor, 7%, 18 years
130,000 = Annuity * 33.9990
Annuity = 130,000 / 33.9990
= $3,823.64
B. Sources of the financial goal.
Money from deposits = Periodic deposit * no. of years
= 3,823.64 * 18
= $68,825.52
Money from interest:
= Financial goal - Money from deposits
= 130,000 - 68,825.52
= $61,174.48
Sodium chlorate crystals are easy to grow in the shape of cubes by allowing a solution of water and sodium chlorate to evaporate slowly. If V is the volume of such a cube with side length x, calculate the derivative when x = 5 mm.
V'(5) = mm3/mm
What does V'(5) mean in this situation?
Answer:
I don't know the answer it is to hard.
Name the three digit number. My ones digit is an even number which is three times as much as my tens digit. My tens digit is the same as my hundreds digit. The sum of all my digits is 10. What number am i?
A. 424
B. 028
C. 226
D. 622
In ΔABC, if AB = 10 and BC = 6, AC can NOT be equal to
Answer:
Step-by-step explanation:
4
