It will take 120 feet for the 36mph car to stop
This question is asking "Where does cosine equal

?"
Based on our unit circle values and the domain of the cos^{-1} function, we see that at 30 degrees, or

, cosine is equal to

.
Answer:

Step-by-step explanation:
We are given that:

And we want to find F'(0).
First, find F(x):
![\displaystyle F'(x) = \frac{d}{dx}\left[ f(3x)]](https://tex.z-dn.net/?f=%5Cdisplaystyle%20F%27%28x%29%20%3D%20%5Cfrac%7Bd%7D%7Bdx%7D%5Cleft%5B%20f%283x%29%5D)
From the chain rule:
![\displaystyle \begin{aligned} F'(x) &= f'(3x) \cdot \frac{d}{dx} \left[ 3x\right] \\ \\ &= 3f'(3x)\end{aligned}](https://tex.z-dn.net/?f=%5Cdisplaystyle%20%5Cbegin%7Baligned%7D%20F%27%28x%29%20%26%3D%20f%27%283x%29%20%5Ccdot%20%5Cfrac%7Bd%7D%7Bdx%7D%20%5Cleft%5B%203x%5Cright%5D%20%5C%5C%20%5C%5C%20%26%3D%203f%27%283x%29%5Cend%7Baligned%7D)
Then:

In conclusion, F'(0) = 15.
The line passes through two points that have the same x-coordinate.
It is a vertical line. To find the slope of a line, use any two points. Subtract the y-coordinates. Subtract the x-coordinates in the same order. Then divide the difference of the y-coordinates by the difference of the x-coordinates. Since in this case, the x-coordinates are both -6, the difference between the x-coordinates is zero. Division by zero is not defined, so the slope of this line is undefined. You can't write its equation in point-slope form, because there is no slope for this line.