2010-09-14, 11:13 PM
I need to prove that the sum of (2r-1)^3, r=1 to n is equal to n^2(2n^2-1) for all positive integers. I'm at a lost of what to do beyond setting it up with the Inductive Assumption and testing it with n=1.
n=1:
(2*1-1)^3 = 1^2(2*1^2-1)
1 = 1
k^2(2k^2-1) + (2(k+1)-1)^3 = (k+1)^2(2(k+1)^2-1)
Math help thread gave me the autolock thing.
n=1:
(2*1-1)^3 = 1^2(2*1^2-1)
1 = 1
k^2(2k^2-1) + (2(k+1)-1)^3 = (k+1)^2(2(k+1)^2-1)
Math help thread gave me the autolock thing.