Harry and Selma start driving from the

Evaluate c (y + 7 sin(x)) dx + (z2 + 9 cos(y)) dy + x3 dz where c is the curve r(t) = sin(t), cos(t), sin(2t) , 0 ≤ t ≤ 2π. (hin

saw5 [17]

Treat $\mathcal C$ as the boundary of the region $\mathcal S$ , where $\mathcal S$ is the part of the surface $z=2xy$ bounded by $\mathcal C$ . We write

$\displaystyle\int_{\mathcal C}(y+7\sin x)\,\mathrm dx+(z^2+9\cos y)\,\mathrm dy+x^3\,\mathrm dz=\int_{\mathcal C}\mathbf f\cdot\mathrm d\mathbf r$

with $\mathbf f=(y+7\sin x,z^2+9\cos y,x^3)$ .

By Stoke's theorem, the line integral is equivalent to the surface integral over $\mathcal S$ of the curl of $\mathbf f$ . We have

$\nabla\times\mathbf f=(-2z,-3x^2,-1)$

so the line integral is equivalent to

$\displaystyle\iint_{\mathcal S}\nabla\times\mathbf f\cdot\mathrm d\mathbf S$
$=\displaystyle\iint_{\mathcal S}\nabla\times\mathbf f\cdot\left(\dfrac{\partial\mathbf s}{\partial u}\times\dfrac{\partial\mathbf s}{\partial v}\right)\,\mathrm du\,\mathrm dv$

where $\mathbf s(u,v)$ is a vector-valued function that parameterizes $\mathcal S$ . In this case, we can take

$\mathbf s(u,v)=(u\cos v,u\sin v,2u^2\cos v\sin v)=(u\cos v,u\sin v,u^2\sin2v)$

with $0\le u\le1$ and $0\le v\le2\pi$ . Then

$\mathrm d\mathbf S=\left(\dfrac{\partial\mathbf s}{\partial u}\times\dfrac{\partial\mathbf s}{\partial v}\right)\,\mathrm du\,\mathrm dv=(2u^2\cos v,2u^2\sin v,-u)\,\mathrm du\,\mathrm dv$

and the integral becomes

$\displaystyle\iint_{\mathcal S}(-2u^2\sin2v,-3u^2\cos^2v,-1)\cdot(2u^2\cos v,2u^2\sin v,-u)\,\mathrm du\,\mathrm dv$
$=\displaystyle\int_{v=0}^{v=2\pi}\int_{u=0}^{u=1}u-6u^4\sin^3v-4u^4\cos v\sin2v\,\mathrm du\,\mathrm dv=\pi$ <span />

4 0

2 years ago

Jordan invested $600 in a savings account. The interest rate is 6% per year. Find the simple interest earned in 3 years. Then fi

olga2289 [7]

In 3 years $108 in interest is earned

principle + interest = $708

8 0

3 years ago

What is it? Eighty-six divided by six??

bixtya [17]

The answer is 14.33333 but you will have to round which you will just have 14.3

6 0

3 years ago

Read 2 more answers

Select all the statements about the situation that are true. Elena makes more money for making 10 calls than Diego makes for was

steposvetlana [31]

Answer:

B, C, E

Step-by-step explanation:

Elena’s aunt pays her $1 for each call she makes to let people know about her aunt’s new business. The table shows how much money Diego receives for washing windows for his neighbors.

Select all the statements about the situation that are true.

A. Elena makes more money for making 10 calls than Diego makes for washing 10 windows.

Elena:

$1 = 1 call

$10 = 10 calls

Diego:

27 windows = $30

10 windows = $x

Cross product

27*x = 30*10

27x = 300

x = 300/27

x = $11.11

Statement A not true

B. Diego makes more money for washing each window than Elena makes for making each call.

Diego:

10 windows = $11.11

Each window = $11.11/10

= $1.11

Statement B is true

C. Elena makes the same amount of money for 20 calls as Diego makes for 18 windows

Elena:

20 calls = $20

Diego:

18 windows = 18 × $1.11

= $19.98

Approximately $20 to the nearest whole dollar

Statement C is true

D. Diego needs to wash 35 windows to make as much money as Elena makes for 40 calls.

Diego

35 × $1.11 = $38.85

Approximately $39

Elena:

40 calls = $40

Statement D is not true

E. The equation y = x, where y is the number of dollars and x is the number of calls, represents Elena’s situation.

Statement E is true

7 0

2 years ago

I need the equation and the answer and how to do it, thank you<3

vazorg [7]

Answer:

19=5+(j times 2/3) j=21

Step-by-step explanation:

While reading out the equation, you understand that Hannah's 19 Jolly Ranchers is what the equation is being set to. 5 more means +5. 2/3 of J can be written as (2/3 times J). You can solve for J by setting the equation to J.

3 0

3 years ago