Chapter 9.10, Problem 1ES

In each part, obtain the Maclaurin series for the function by making an appropriate substitution in the Maclaurin series for $1/(1-x).$ Include the general term in your answer, and state the radius of convergence of the series.

$\begin{array}{l}\left(\text{a}\right)\frac{1}{1+x}\\ \left(\text{b}\right)\frac{1}{1-x^2}\\ \left(\text{c}\right)\frac{1}{1-2x}\\ \left(\text{d}\right)\frac{1}{2-x}\end{array}$