Question

Polar Coordinates - Rose Petal: The petal of the rose r=6cos(5theta) that contains a portion of the positive x axis lies between 2 angles. What are they?

Answer 1

Just thinking out loud. When theta = 0 we have cos(5theta) = cos(0) = 1, maximum value for cos(5theta). To get cos(5theta) to 0 (in the positive, counterclockwise direction) we'd need to have 5theta = π/2. So then theta would have to be . . . ?

Answer 2

So I had that at first, and had entered pi/10 as the smaller angle, but apparently they wanted -pi/10. Thanks for your help.

Answer 3

The problem asks for 2 angles, so one would be positive and the other negative (or 2π minus the first).