I'm having trouble understanding bases outside of R^n; I've got a handle on those I think. Here are some examples: 13. In C(-Pi,Pi), find the dimension of the subspace spanned by 1, cos(2x), and cos^2(x). 14. Find the dimension of the subspace of P3 spanned by x, x-1 , x^2+1, x^2-1 I really don't know how to begin either of these Thanks for any input.