Hi :) Is this a quadratic function?

Consider F and C below. F(x, y, z) = y2 sin(z) i + 2xy sin(z) j + xy2 cos(z) k C: r(t) = t2 i + sin(t) j + t k, 0 ≤ t ≤ π (a) Fi

Liono4ka [1.6K]

Answer:

a) $f (x,y,z)= xy^2\sin(z)$

b) $\int_C F \cdot dr =0$

Step-by-step explanation:

Recall that given a function f(x,y,z) then $\nabla f = (\frac{\partial f}{\partial x},\frac{\partial f}{\partial y},\frac{\partial f}{\partial z})$ . To find f, we will assume it exists and then we will find its form by integration.

First assume that F = $\nabla f$ . This implies that

$\frac{\partial f}{\partial x} = y^2\sin(z)$ if we integrate with respect to x we get that

$f(x,y,z) = xy^2\sin(z) + g(y,z)$ for some function g(y,z). If we take the derivative of this equation with respect to y, we get

$\frac{\partial f}{\partial y} = 2xy\sin(z) + \frac{\partial g}{\partial y}$

This must be equal to the second component of F. Then

$2xy\sin(z) + \frac{\partial g}{\partial y}=2xy\sin(z)$

This implies that $\frac{\partial g}{\partial y}=0$ , which means that g depends on z only. So $f(x,y,z) = xy^2\sin(z) + g(z)$

Taking the derivative with respect to z and making it equal to the third component of F, we get

$xy^2\cos(z)+\frac{dg}{dz} = xy^2\cos(z)$

which implies that $\frac{dg}{dz}=0$ which means that g(z) = K, where K is a constant. So

$f (x,y,z)= xy^2\sin(z)$

b) To evaluate $\int_C F \cdot dr$ we can evaluate it by using f. We can calculate the value of f at the initial and final point of C and the subtract them as follows.

$\int_C F \cdot dr = f(r(\pi))-f(r(0))$

Recall that $r(\pi) = (\pi^2, 0, \pi)$ so $f(r(\pi)) = \pi^2\cdot 0 \cdot \sin(\pi) = 0$

Also $r(0) = (0, 0, 0)$ so $f(r(0)) = 0^2\cdot 0 \cdot \sin(0) = 0$

So $\int_C F \cdot dr =0$

5 0

2 years ago

PLZ HELP ASAP. What is the measure of B?

KATRIN_1 [288]

Answer:

C. 55°

Step-by-step explanation:

Note the total measurement of angles for a triangle. The total measurement of all angles in a triangle = 180°

Note that m∠C is a right angle (as shown through the square), and that right angles = 90°

Subtract to find the measurement of the unknown angle (∠B)

∠B = 180 - (∠A + ∠C)

∠B = 180 - (35 + 90)

Simplify. Combine like terms. First, add (solve parenthesis), then subtract.

∠B = 180 - (125)

∠B = 55

m∠B = C. 55°

~

7 0

3 years ago

Read 2 more answers

Please help me with this and thank you

katovenus [111]

Answer:

The answer is D

Step-by-step explanation:

(12 + 6) x ( 11 - 7) = 72

18 x 4 = 72

72 = 72

5 0

3 years ago

Read 2 more answers

Help its ugent ill mark brainleyest

Brilliant_brown [7]

Answer:

more than one triangle

Step-by-step explanation:

4 0

2 years ago

The diameter of a sphere is 12 inches.what is the volume of the sphere to the nearest cubic inch ?

miss Akunina [59]

Answer:

The volume of the sphere is 288π or 904.778 cubic inches.

Step-by-step explanation:

$given \\ diameter \: of \: sphere \: = 12 \: inches \\ radius \: of \: sphere \: = \frac{diameter}{2} \\ radius \: = \frac{12}{2} = 6 \: inches \\ volume \: of \: sphere \: = \frac{4}{3} \pi \: {r}^{3} \\ here \: r \: = \: 6 \: in \\ volume \: of \: sphere = \frac{4}{3} \pi \: {6}^{3} \\ \\ volume \: of \: sphere = \frac{4}{3} \pi \times 216 \\ \: \: = 4\pi \times 72 \\ \: \: = 288\pi \\ \: \: = 904.778 \: cubic \: inches$

HAVE A NICE DAY!

THANKS FOR GIVING ME THE OPPORTUNITY TO ANSWER YOUR QUESTION. 

4 0

3 years ago