help on to find probability density function

hey guys, i am really confused on something.here is the thing:

i have;

i=x+(x^2-y)^(1/2)

and here x is uniform distribution on (a,b)

y is uniform distribution on (c,d)

x and y independent

and there is no information about a,b,c,d.but if you need you can assume anything like a>c.

i need to find the probability density function of i but how??????

actually i dont know how to start!!