How Gauss Did It 1 + 2 + 3 + . . . + n =

2. Triangular Numbers Tn = 1 + 2 + 3 + . . . + n =

3. Sum of Squares (understand how to find the sum using the proofs in both parts)

12 + 22 + 32 + . . . + n2 =

7. Exponential Sums (Do parts a and b only)

a) 2 0 + 21 + 22 + 23 + . . . + 2n–1 =

b) a 0 + a 1 + a 2 + a 3 + . . . + a n–1 =