Which expression is equivalent to the partial fraction decomposition of 1x2−1\frac{1}{x^2-1}x2−11?
\frac{1}{2(x-1)} - \frac{1}{2(x+1)}
\frac{1}{x-1} + \frac{1}{x+1}
\frac{1}{2(x+1)} - \frac{1}{2(x-1)}
\frac{1}{x-1} - \frac{1}{x+1}