Question

r = 1 - cos(theta)
0 < theta < 2pi

find where the tangents are horizontal and vertical

Answer 1

Find the derivative and set it equal to zero for horizontal.

Answer 2

i get \[\frac{dy}{d \theta} = \sin^2\theta - \cos^2\theta + \cos \theta\]

Answer 3

so its zero when theta is 0 , pi and 2pi right??

Answer 4

\[r'=\sin(\Theta)\]

Answer 5

WAIT! Are you in polar mode?

Answer 6

You dont have to use \[x = rcos(\theta) \space and \space y= rsin(\theta)\] ??? and then plug in the r you have??

Answer 7

Yes polar mode

Answer 8

Yes you do - Ignore my responses.
>.<

Answer 9

Ok i did that and got the derivative that i typed above