Write S SN = S = 1 as a telescoping series and find its sum. Σ = n=9 n(n-1) 1 -

Use the formula for the sum of the first ii terms of an arithmetic series to find the sum of the first eleven terms of the arithmetic series 2.5,4,5.5,

Write 0.65 as an infinite geometric series using summation notation. Then use the formula for finding the sum of an infinite geometric series to convert 0.65 to a fraction.