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3 years ago

The product of 4 and a number

Mathematics

2 answers:

erma4kov [3.2K]3 years ago

5 0

Answer:

Step-by-step explanation:

x in this case would be the number

sukhopar [10]3 years ago

4 0

Answer:

4*x

Step-by-step explanation:

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Factor completely.<br> x² - 3x² - 4

Ber [7]

Answer:

-2(x^2+2)

Step-by-step explanation:

1. x^2-3x^2-4
= -2x^2-4
2. -2(x^2+2) factor completely :)

7 0

1 year ago

Read 2 more answers

Choice 1: Angela and Kellie went to lunch. Their bill before tax was $20.00. Tax is 8%. How much tax should

Zolol [24]

Answer:

$1.60

Step-by-step explanation:

Amount of tax paid = percentage of tax to be paid x bill before tax

0.08 x $20 = $1.60

4 0

3 years ago

CAN SOMEONE PLEASE HELP ME???<br> ↓↓↓↓↓↓↓↓↓↓↓↓↓↓↓↓↓↓↓↓↓↓↓↓↓↓↓↓↓∵

nata0808 [166]

Answer:

it is number 3 (-1/5)

Step-by-step explanation:

8 0

3 years ago

Read 2 more answers

A torus is formed by rotating a circle of radius r about a line in the plane of the circle that is a distance R (> r) from th

jeyben [28]

Consider a circle with radius $r$ centered at some point $(R+r,0)$ on the $x$ -axis. This circle has equation

$(x-(R+r))^2+y^2=r^2$

Revolve the region bounded by this circle across the $y$ -axis to get a torus. Using the shell method, the volume of the resulting torus is

$\displaystyle2\pi\int_R^{R+2r}2xy\,\mathrm dx$

where $2y=\sqrt{r^2-(x-(R+r))^2}-(-\sqrt{r^2-(x-(R+r))^2})=2\sqrt{r^2-(x-(R+r))^2}$ .

So the volume is

$\displaystyle4\pi\int_R^{R+2r}x\sqrt{r^2-(x-(R+r))^2}\,\mathrm dx$

Substitute

$x-(R+r)=r\sin t\implies\mathrm dx=r\cos t\,\mathrm dt$

and the integral becomes

$\displaystyle4\pi r^2\int_{-\pi/2}^{\pi/2}(R+r+r\sin t)\cos^2t\,\mathrm dt$

Notice that $\sin t\cos^2t$ is an odd function, so the integral over $\left[-\frac\pi2,\frac\pi2\right]$ is 0. This leaves us with

$\displaystyle4\pi r^2(R+r)\int_{-\pi/2}^{\pi/2}\cos^2t\,\mathrm dt$

Write

$\cos^2t=\dfrac{1+\cos(2t)}2$

so the volume is

$\displaystyle2\pi r^2(R+r)\int_{-\pi/2}^{\pi/2}(1+\cos(2t))\,\mathrm dt=\boxed{2\pi^2r^2(R+r)}$

6 0

2 years ago

This question is confusing me

Ksenya-84 [330]

It’s C that’s the only one that works

6 0

2 years ago