Note that 1/(1 + x)^2 = - d/dx [1/(1 + x)]

and you know the power series representation as TPH calculated it for you here

turn his answer into a single expression (it would be SUM{n goes from 0 to infinity} (-1)^n *x^n) and differentiate that expression, and add a minus sign in front and you will have the answer for part (a). the other parts are similar.