In аdditiоn tо the Integrаl аnd Series Table (which shоuld open in a separate tab or window), you also have access to the following two formulas: ∑ i = 0 N − 1 a x i = a ( 1 − x N ) 1 − x {"version":"1.1","math":"sum_{i=0}^{N-1} ax^i =frac{a(1-x^N)}{1-x}"} ∑ i = 0 ∞ a x i = a 1 − x when | x |