b) Assuming that it is true for n=k , you get that 1+2+3+?+k=\frac{k(k+1)}{2} Add (k +1) to both sides, and show it is true for n-k +1, by simplifying the

right side of the following equation. 1+2+3+?+k+(k+1)=\frac{k(k+1)}{2}+(k+1) =\frac{k(k+1)}{2}+\frac{2(k+1)}{2} 1. Use Mathematical Induction to prove that 1+2+3+?+ n =n(n +1) /2 for all natural numbers, n. a) Verify that it is true for n=1. \frac{1(1+1)}{2}=