Probability question - calculating marginal pdfs

[jaejoon89]

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

Calculate the marginal probability distribution function of X given joint pdf

f(x,y) = 15x^2 y for 0 <= x <= y <= 1
f(x,y) = 0 otherwise

2. Relevant equations


f_x (x) = integral of f(x,y) dy

3. The attempt at a solution

I've got no idea what the bounds are for this integral.

Also, would it be easier to do it in polar coordinates?

[Dick]

0<=x<=y<=1. For a fixed value of x, doesn't y go from x to 1? I'm not sure why this is confusing you and I don't think polar coordinates will help one bit.