Ask question

Ask question

All categories

2 years ago

13

Mr. Washington purchased three cell phones. Each cell phone cost one hundred fifty dollars. What is the total she paid for the c

ell phones?

1 answer:

Kamila [148]2 years ago

7 0

Answer:

The answer is $450

Step-by-step explanation:

You need to do 150+150+150=450

or

150x3=450

You might be interested in

Solution for dy/dx+xsin 2 y=x^3 cos^2y

vichka [17]

Rearrange the ODE as

$\dfrac{\mathrm dy}{\mathrm dx}+x\sin2y=x^3\cos^2y$
$\sec^2y\dfrac{\mathrm dy}{\mathrm dx}+x\sin2y\sec^2y=x^3$

Take $u=\tan y$ , so that $\dfrac{\mathrm du}{\mathrm dx}=\sec^2y\dfrac{\mathrm dy}{\mathrm dx}$ .

Supposing that $|y|$ , we have $\tan^{-1}u=y$ , from which it follows that

$\sin2y=2\sin y\cos y=2\dfrac u{\sqrt{u^2+1}}\dfrac1{\sqrt{u^2+1}}=\dfrac{2u}{u^2+1}$
$\sec^2y=1+\tan^2y=1+u^2$

So we can write the ODE as

$\dfrac{\mathrm du}{\mathrm dx}+2xu=x^3$

which is linear in $u$ . Multiplying both sides by $e^{x^2}$ , we have

$e^{x^2}\dfrac{\mathrm du}{\mathrm dx}+2xe^{x^2}u=x^3e^{x^2}$
$\dfrac{\mathrm d}{\mathrm dx}\bigg[e^{x^2}u\bigg]=x^3e^{x^2}$

Integrate both sides with respect to $x$ :

$\displaystyle\int\frac{\mathrm d}{\mathrm dx}\bigg[e^{x^2}u\bigg]\,\mathrm dx=\int x^3e^{x^2}\,\mathrm dx$
$e^{x^2}u=\displaystyle\int x^3e^{x^2}\,\mathrm dx$

Substitute $t=x^2$ , so that $\mathrm dt=2x\,\mathrm dx$ . Then

$\displaystyle\int x^3e^{x^2}\,\mathrm dx=\frac12\int 2xx^2e^{x^2}\,\mathrm dx=\frac12\int te^t\,\mathrm dt$

Integrate the right hand side by parts using

$f=t\implies\mathrm df=\mathrm dt$
$\mathrm dg=e^t\,\mathrm dt\implies g=e^t$
$\displaystyle\frac12\int te^t\,\mathrm dt=\frac12\left(te^t-\int e^t\,\mathrm dt\right)$

You should end up with

$e^{x^2}u=\dfrac12e^{x^2}(x^2-1)+C$
$u=\dfrac{x^2-1}2+Ce^{-x^2}$
$\tan y=\dfrac{x^2-1}2+Ce^{-x^2}$

and provided that we restrict $|y|$ , we can write

$y=\tan^{-1}\left(\dfrac{x^2-1}2+Ce^{-x^2}\right)$

5 0

3 years ago

What kind of angle is formed by the tangent to a circle and a radius of that circle?

Vsevolod [243]

A tangent is always perpendicular to the radius at the point of tangency.

A right angle.

6 0

2 years ago

Read 2 more answers

Standard form for 78 hundreds 58 tens 19 ones

Nastasia [14]

Answer:

8399

Step-by-step explanation:

78*100=7800

58*10=580

7800+580+19=8399

4 0

3 years ago

A number c multiplied by -2 is no less than - 3. Write this word sentence as an inequality.

antiseptic1488 [7]

Answer: -3 ≤ -2c

Step-by-step explanation:

First multiply C by -2, and make sure it's not less than -3. It can be -3, but it can't be less than.

3 0

3 years ago

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

andrew-mc [135]

Answer:

Y

Step-by-step explanation:

5 0

2 years ago