Find the derivative of f(x)=ln(1+x1−x)f(x) = \ln(\sqrt{\frac{1+x}{1-x}})f(x)=ln(1−x1+x).
11−x2\frac{1}{1-x^2}1−x21
11+x2\frac{1}{1+x^2}1+x21
21−x2\frac{2}{1-x^2}1−x22
x1−x2\frac{x}{1-x^2}1−x2x