Induction proof - Stumped as to how a certain step was achieved

34 Views Asked by At

The proof in question.

The part I've underlined is what I don't understand - where did the second (k+1) come from? Did the author make a substitution that I am not registering?

1

There are 1 best solutions below

1
On BEST ANSWER

Take a look at the indices of summation. On the LHS of the equation, it goes up to $k+1$, but on the RHS, it goes to $k$. The last term is brought out of the summation, which is what you underlined.