The wedge in the first octant and from the cylinder y^2 + z^2 <= 1 by the planes

y=x, x=0, z=0

First..

i find the range for z..; 0 <=z<= sqrt(1- y^2)

then...

i find the range for y..; let z =0

0<=y<=1

next, if i let z = y = 0

how am i going to find the range for x?