Question

I'm trying to prove a series using induction. I know where I've gotten to is correct, I just can't figure out the algebra: (-1)^k(k)(k+1)/2 + (-1)^(k+1)(k+1)^2

adding these together I should get the original equation (-1)^n(n)(n+1)/2 where n=k+1 in this case. Please help

Answer 1

Anyone, please?

Answer 2

I think I got it, (-1)^k [k^2+k-2k^2-4k-2]/2 = (-1)^k[-k^2-3k-2]/2 = (-1)^(k+1)[(k+1)(k+2)]/2

Answer 3

correct