1. Which of the following statements is NOT a property of parallelograms?

Use the given transformation to evaluate the integral. 9 x − 3y 2x − y dA, R where R is the parallelogram enclosed by the lines

hichkok12 [17]

$\displaystyle\iint_R(9x-3y)(2x-y)\,\mathrm dA$

$\begin{cases}u=x-3y\\v=2x-y\end{cases}\implies\begin{cases}x=\frac{3v-u}5\\y=\frac{v-2u}5\end{cases}\implies\mathrm dA=|\det J|\,\mathrm du\,\mathrm dv$

where $J$ is the Jacobian matrix for the transformation,

$J=\begin{bmatrix}u_x&u_y\\v_x&v_y\end{bmatrix}=\begin{bmatrix}-\dfrac15&\dfrac35\\\\-\dfrac25&\dfrac15\end{bmatrix}\implies|\det J|=\dfrac15$

We have

$9x-3y=8x+x-3y=\dfrac85(3v-u)+u=\dfrac{24v-3u}5$

so that the integral is

$\displaystyle\frac1{25}\int_9^{10}\int_0^{10}(24v-3u)v\,\mathrm du\,\mathrm dv=\boxed{\frac{4051}5}$

5 0

4 years ago

Abercrombie is having a sale of 25% off your purchase. You plan to buy a fleece sweatshirt that has a price tag of $72. How much

Oduvanchick [21]

Answer:

$18

Step-by-step explanation:

You save 25% 0f 72 (72x.25)

3 0

3 years ago

Decide if the following is a true or false statement - explain how you know

Sophie [7]

Answer:

False

Step-by-step explanation:

The equation equals -1/2 - 4.25 which is -4.75, which is negative.

Hope that helps!

5 0

3 years ago

If alex is 14 years old, and ben is 17 years old, in how many years will the sum of their ages be 169 years?

navik [9.2K]

169... because 14+x + 17+x = 169

3 0

3 years ago

Read 2 more answers

Because of safety considerations, in May 2003 the Federal Aviation Administration (FAA) changed its guidelines for how small com

Rasek [7]

Answer:

a) The 95% confidence interval for the mean summer weight (including carry-on luggage) of Frontier Airlines passengers is between 179 and 187 pounds. This means that we are 95% sure that the mean summer weight of all Frontier Airlines passengers is between these two values.

b)

The 95% confidence interval for the mean winter weight (including carry-on luggage) of Frontier Airlines passengers is between 185.4 pounds and 194.6 pounds. This means that we are 95% sure that the mean winter weight of all Frontier Airlines passengers is between these two values.

c) They are respected, as the upper bound of both intervals is below the new FAA recommendations.

Step-by-step explanation:

We have the standard deviation for the sample, which means that the t-distribution is used to solve these questions.

Question a:

The first step to solve this problem is finding how many degrees of freedom, we have. This is the sample size subtracted by 1. So

df = 100 - 1 = 99

95% confidence interval

Now, we have to find a value of T, which is found looking at the t table, with 99 degrees of freedom(y-axis) and a confidence level of $1 - \frac{1 - 0.95}{2} = 0.975$ . So we have T = 1.9842

The margin of error is:

$M = T\frac{s}{\sqrt{n}} = 1.9842\frac{20}{\sqrt{100}} = 4$

In which s is the standard deviation of the sample and n is the size of the sample.

The lower end of the interval is the sample mean subtracted by M. So it is 183 - 4 = 179 pounds.

The upper end of the interval is the sample mean added to M. So it is 183 + 4 = 187 pounds.

The 95% confidence interval for the mean summer weight (including carry-on luggage) of Frontier Airlines passengers is between 179 and 187 pounds. This means that we are 95% sure that the mean summer weight of all Frontier Airlines passengers is between these two values.

Question b:

Critical value is the same(same sample size and confidence level).

The margin of error is:

$M = T\frac{s}{\sqrt{n}} = 1.9842\frac{23}{\sqrt{100}} = 4.6$

The lower end of the interval is the sample mean subtracted by M. So it is 190 - 4.6 = 185.4 pounds.

The upper end of the interval is the sample mean added to M. So it is 190 + 4.6 = 194.6 pounds.

The 95% confidence interval for the mean winter weight (including carry-on luggage) of Frontier Airlines passengers is between 185.4 pounds and 194.6 pounds. This means that we are 95% sure that the mean winter weight of all Frontier Airlines passengers is between these two values.

c. The new FAA recommendations are 190 pounds for summer and 195 pounds for winter. Comment on these recommendations in light of the confidence interval estimates from Parts (a) and (b).

They are respected, as the upper bound of both intervals is below the new FAA recommendations.

7 0

3 years ago