Answer number 2 only

Consider the funet ion 1. Use the geometric series to nd a power series representation for f(a:) about 0 and give its interval of convergence. I 2. By rst differentiating the power series obtained in (1.1), nd a power series representation for 411172 9(37) 2 m: then use an appropriate value of a: to determine (the sum of) ? 2 +1 Z:n+1' nzl]