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2 years ago

2. (1 point)

Mathematics

1 answer:

netineya [11]2 years ago

6 0

Answer:

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Consider the following region R and the vector field F. a. Compute the two-dimensional curl of the vector field. b. Evaluate bo

Shalnov [3]

Looks like we're given

$\vec F(x,y)=\langle-x,-y\rangle$

which in three dimensions could be expressed as

$\vec F(x,y)=\langle-x,-y,0\rangle$

and this has curl

$\mathrm{curl}\vec F=\langle0_y-(-y)_z,-(0_x-(-x)_z),(-y)_x-(-x)_y\rangle=\langle0,0,0\rangle$

which confirms the two-dimensional curl is 0.

It also looks like the region $R$ is the disk $x^2+y^2\le5$ . Green's theorem says the integral of $\vec F$ along the boundary of $R$ is equal to the integral of the two-dimensional curl of $\vec F$ over the interior of $R$ :

$\displaystyle\int_{\partial R}\vec F\cdot\mathrm d\vec r=\iint_R\mathrm{curl}\vec F\,\mathrm dA$

which we know to be 0, since the curl itself is 0. To verify this, we can parameterize the boundary of $R$ by

$\vec r(t)=\langle\sqrt5\cos t,\sqrt5\sin t\rangle\implies\vec r'(t)=\langle-\sqrt5\sin t,\sqrt5\cos t\rangle$

$\implies\mathrm d\vec r=\vec r'(t)\,\mathrm dt=\sqrt5\langle-\sin t,\cos t\rangle\,\mathrm dt$

with $0\le t\le2\pi$ . Then

$\displaystyle\int_{\partial R}\vec F\cdot\mathrm d\vec r=\int_0^{2\pi}\langle-\sqrt5\cos t,-\sqrt5\sin t\rangle\cdot\langle-\sqrt5\sin t,\sqrt5\cos t\rangle\,\mathrm dt$

$=\displaystyle5\int_0^{2\pi}(\sin t\cos t-\sin t\cos t)\,\mathrm dt=0$

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3 years ago

John’s mathematics teacher drew a triangle that had a 70° angle and a 20° angle. What is the measure of the third angle in the t

kari74 [83]

All triangles interior angles equal 180
So these 3 angles = 180

7 0

3 years ago

17. El precio de los terrenos en Lima es proporcional al área e inversamente proporcional a su distancia con respecto al centro

grin007 [14]

Answer:

375000

Step-by-step explanation:

We have that in this case the following proportion would be fulfilled:

Price * Distance / area

Now, we have that for a distance of 45 km and an area of 900 m ^ 2 the price is 250,000, now for a distance of 40 km but with an area of 1,200 m ^ 2, how would the price be, we replace:

250000 * 45/900 = P * 40/1200

12500 * 1200/40 = P

P = 375000

Which means that for these conditions the price is 375000.

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3 years ago

I need to know what the answer is?<br>is it x,y,z,or w?

andrew-mc [135]

Answer:

Step-by-step explanation:

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3 years ago

A dump truck pours sand into a container in the shape of a rectangular prism with a square base of length 2 feet. The height, h,

aev [14]

Answer:

I think the answer is 24 minutes!

Step-by-step explanation:

I hope this helps!

5 0

2 years ago

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