# Thread: Discreet Systems algebra question.

1. ## Discreet Systems algebra question.

Im going over a solution to the following problem, and was stuck trying to figure out how to get the final answer. If i substitute (n-1)/2 for k i would get:

((n-1)/2)( ((n-1)/2 ) + 1) and not the final answer given in the solution given.

problem 28:

prove the following.

the solution:

2. You're saying that they aren't the same because...
( ((n-1)/2 ) + 1) isn't (n + 1)/2 ???

In fact, they are equal.