Question from ireimaima, a student:

Hi.. Can u please help me with this question.. I find that when i test eg: n=2 for n (n+1) /4, it seems that it does not giving me the right answer of 1^3 + 2^3 = 9 but 3/2... i'm confuse..can u please help me..thanks so much

Prove that: 1^3 + 2^3 + 3^3 +4^3 ... n^3 = n (n+1) /4

Ireimaima,

You are correct the expression you have is not correct It should be

1^{3} + 2^{3} + 3^{3} + 4^{3} ... n^{3} = [n (n+1) /2]^{2}

Now can you prove it by induction?

Penny