Mathematical Induction Question

Hello, I have this problem that I can't figure out. I don't think I have too much issue with a simple version of maths induction but this particular question I can't seem to figure out.

The question is:

Use mathematical induction to prove that for every positive integer

*n*

1^

3 + 2^3 + 3^3 + *. . . *+ *n^*3 = ((*n *(*n *+ 1))/2)^2

I can only get to this stage:

((n(n + 1))/2)^2 + (n + 1)^3 = (((*n + 1)*((*n + 1) *+ 1))/2)^2

I would greatly appreciate it if some wiz could help me out.

Thanks.