Cesium 2013

The math homework that is due next week is:

Prove the following by induction:

1)
a₁+(a₁+d)+(a₁+2d)+...+(a₁+(n-1)d)= (n(2a₁+(n-1)d)/2

2)
g₁+g₁ x r+g₁ x r²+...+g₁ x r^n-1= (g₁(1 - rⁿ))/(1-r)