# math

posted by
**Wayne**
.

Use the method of differences to prove the following formulas

1) ∑_(r=1)^n▒〖r=(n(n+1))/2〗

2) ∑_(r=1)^n▒〖r^2=(n(n+1)(2n+1))/6〗

posted by
**Wayne**
.

Use the method of differences to prove the following formulas

1) ∑_(r=1)^n▒〖r=(n(n+1))/2〗

2) ∑_(r=1)^n▒〖r^2=(n(n+1)(2n+1))/6〗