# Homework Help: Trace question

1. May 22, 2006

### dyanmcc

I'm having trouble with this: Prove that if P is a linear map from V to V and satisfies P^2 = P, then trace P is a nonnegative integer.

I know if I find the eignevalues , their sum equals trace P. But how do I find them here?

any thoughts?

Thanks

2. May 22, 2006

### Hurkyl

Staff Emeritus