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zhannawk [14.2K]

2 years ago

12

Rick rents a car from a company that charges him $25 per day plus 10 cents per mile driven. Which expression can represent the a

mount he owed on a recent rental?

2 answers:

Vinvika [58]2 years ago

7 0

Answer:

25d +10m = the amount he owed on a recent rental

Step-by-step explanation:

Rate as brainliest

scoundrel [369]2 years ago

5 0

Answer:

25x + 0.1y

Step-by-step explanation:

I did the test it is all right. :)

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6 0

2 years ago

Elan Coil [88]

By definition, the number $\pi$ is the ratio between the circumference and the diameter:

$\pi=\dfrac{C}{d}$

This implies that

$C=\pi d$

And so your circumference is $8\pi$

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2 years ago

10.44 is 14.4% of what number?

kipiarov [429]

The answer for that is .. 17?

3 0

3 years ago

Read 2 more answers

Please help me on this one!

MatroZZZ [7]

On which one? You did not provide anything for me to help you with.

4 0

3 years ago

15. If x=a Sin2t (I+Cos2t) and y=b Cos 2t (1-Cos2t) then find<br>dy/dx at =22/7*4<br>

Sav [38]

By the chain rule,

$\dfrac{\mathrm dy}{\mathrm dx}=\dfrac{\mathrm dy}{\mathrm dt}\dfrac{\mathrm dt}{\mathrm dx}\implies\dfrac{\mathrm dy}{\mathrm dx}=\dfrac{\frac{\mathrm dy}{\mathrm dt}}{\frac{\mathrm dx}{\mathrm dt}}$

It looks like we're given

$\begin{cases}x=a\sin(2t)(1+\cos(2t))\\y=b\cos(2t)(1-\cos(2t))\end{cases}$

where <em>a</em> and <em>b</em> are presumably constant.

Recall that

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

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

so that

$\begin{cases}x=2a\sin(2t)\cos^2t\\y=2b\cos(2t)\sin^2t\end{cases}$

Then we have

$\dfrac{\mathrm dx}{\mathrm dt}=4a\cos(2t)\cos^2t-4a\sin(2t)\cos t\sin t$

$\dfrac{\mathrm dy}{\mathrm dt}=-4b\sin(2t)\sin^2t+4b\cos(2t)\sin t\cos t$

$\implies\dfrac{\mathrm dy}{\mathrm dx}=\dfrac{4b\cos(2t)\sin t\cos t-4b\sin(2t)\sin^2}{4a\cos(2t)\cos^2t-4a\sin(2t)\cos t\sin t}$

$\implies\boxed{\dfrac{\mathrm dy}{\mathrm dx}=\dfrac ba\tan t}$

where the last reduction follows from dividing through everything by $\cos(2t)\cos^2t$ and simplifying.

I'm not sure at which point you're supposed to evaluate the derivative (22/7*4, as in 88/7? or something else?), so I'll leave that to you.

8 0

3 years ago