# Homework Help: Parametric equation question

1. May 23, 2010

### stau40

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

Find an equation y=f(x) for the parametric curve x = cos (theta) y = cos (theta) + sin^(2) (theta)

2. Relevant equations

3. The attempt at a solution
I know I need to solve for theta but I'm not sure how to go about this. Can I plug x into the theta's in y or do I use the trig identity sin^(2) + cos^(2) = 1? Thanks in advance!

2. May 23, 2010

### gabbagabbahey

Use the fact that $\cos\theta=x$ and $\sin^2\theta=1-\cos^2\theta$.