Simplify 11−x+11+x+21+x2\frac{1}{1-x} + \frac{1}{1+x} + \frac{2}{1+x^2}1−x1+1+x1+1+x22.
41−x4\frac{4}{1-x^4}1−x44
4x21−x4\frac{4x^2}{1-x^4}1−x44x2
21−x4\frac{2}{1-x^4}1−x42
41+x4\frac{4}{1+x^4}1+x44