# Homework Help: Graph of a cardiod

1. Feb 15, 2012

### bobsmith76

1. The problem statement, all variables and given/known data

3. The attempt at a solution

I don't see how they get

1 - cos (pi/3) = 1/2

cos (pi/3) = √3/2

1 - √3/2 = .14, not .5 like the book says

for the other figures I agree with the book.

2. Feb 15, 2012

### Staff: Mentor

What's not to get? cos($\pi$/3) = 1/2.

You need to brush up on your trig.
No, this is not true. sin($\pi$/3) = √3/2.

3. Feb 15, 2012

### bobsmith76

never mind, I was mixing pi/6 up with pi/3