My question is to prove this by Induction, 1^3 + 2^3 + … + n^3 = n^2(n+1)^2/4

I got the base step, but I am struggling on the Inductive Step. Here is what I have:

Assume Pk is true

Consider Pk+1

Σ i^3 (from i=1 to k+1) = Σ i^3 (from i=1 to k) + (k+1)

= k^2(k+1)/4 + (k+1)

= (k+1)[k(k+1)/4 + 1]

= (k+1)[k(k+1)+4/4]

Therefore, by Induction Pn is true for all n≥1

I was told that my answer is incorrect. Any help on where I went wrong?