Which table represents a linear function?

Electric charge is distributed over the disk x2 + y2 ≤ 16 so that the charge density at (x, y) is rho(x, y) = 2x + 2y + 2x2 + 2y

professor190 [17]

Answer:

Required total charge is $256\pi$ coulombs per square meter.

Step-by-step explanation:

Given electric charge is dristributed over the disk,

$x^2=y^2\leq 16$ so that the charge density at (x,y) is,

$\rho (x,y)=2x+2y+2x^2+2y^2$

To find total charge on the disk let Q be the total charge and $x=r\cos\theta,y=r\sin\theta$ so that,

$Q={\int\int}_Q\rho(x,y) dA$ where A is the surface of disk.

$=\int_{0}^{2\pi}\int_{0}^{4}(2x+2y+2x^2+2y^2)dA$

$=\int_{0}^{2\pi}\int_{0}^{4}(2r\cos\theta+2r\sin\theta+2r^2 \cos^{2}\theta+2r^2\sin^2\theta)rdrd\theta$

$=2\int_{0}^{2\pi}\int_{0}^{4}r^2(\cos\theta+\sin\theta)drd\theta+2\int_{0}^{2\pi}\int_{0}^{4}r^3drd\theta$

$=\frac{2}{3}\int_{0}^{2\pi}(\sin\theta+\cos\theta)\Big[r^3\Big]_{0}^{4}d\theta+2\int_{0}^{2\pi}\Big[\frac{r^4}{4}\Big]d\theta$

$=\frac{128}{3}\int_{0}^{2\pi}(\sin\theta+\cos\theta)d\theta+128\int_{0}^{2\pi}d\theta$

$=\frac{128}{3}\Big[\sin\theta-\cos\theta\Big]_{0}^{2\pi}+128\times 2\pi$

$=\frac{128}{3}\Big[\sin 2\pi-\cos 2\pi-\sin 0+\cos 0\Big]+256\pi$

$=256\pi$

Hence total charge is $256\pi$ coulombs per square meter.

3 0

3 years ago

If you cycled for 3 hours and travelled 54 km calculate your average speed

goldenfox [79]

Answer:

162 km per hour

Step-by-step explanation:

Hi!

Speed=Distance x Time

So... 3 x 54 = 162

Hope this helps :)

3 0

3 years ago

Read 2 more answers

Help me , I need i whole number

ad-work [718]

Answer:

16

Step-by-step explanation:

4 goes into 64 evenly 16 times

5 0

2 years ago

What do the differences between the points (as shown on the graph) represent?

pishuonlain [190]

Answer:

They represent the rise and run of the graph.

Step-by-step explanation:

The difference between the x-axis of the points represents the "run" of the graph (or how much you should run along x-axis to get to the next point.)

The difference between the y-axis of of the points represents the "rise" of the graph (or how much you should rise up the y-xis to get to the next point).

The ratio of rise to run is the slope of the graph, which tells us how many steps should we take on the y-axis for every step we move forward on the x-axis.

8 0

3 years ago

A parabola can be drawn given a focus of (6,-1) and a directrix of y = 9. What can be said about the parabola?

zavuch27 [327]

Answer:

Since the focus is at (-6,-11) and the directrix is at y=9:

The vertex is halfway between the focus and the directrix, so the vertex is at (-6,-1). (Draw this on graph paper if that doesn't make sense.)

The general form (conics form) of a parabola: 4p(y-k)=(x-h)^2 (vertex is (h,k) and "p" is the distance between the focus and vertex (or between vertex and directrix)).

(h,k) = (-6,-1)

p = 10 (distance between focus and vertex), so 4p = 40.

Therefore:

40(y+1)=(x+6)^2

Or if you need to rearrange to "vertex form": y=(1/40)(x+6)^2 - 1

Step-by-step explanation:

3 0

3 years ago