Question

To prove that 1 + 2 + 3 + ... + n = n(n + 1)/1 by mathematical induction, the first step would be

Answer 1

you just have to identify the first step
here are the choices
A. Show that 1 = 1(1 + 1)/2
B. Show that 1 + 2 = 2(2 + 1)/2
C. Show that 1 + 2 + 3 = 3(3 + 1)/2
D. Assume that 1 + 2 + ... + k = k(k + 1)/2

Answer 2

pretty lost
I'll just go watch a video or something..

Answer 3

thanks for your help though