Question

Resolve into partial fractions

$\frac{1}{(x − 1) (x + 1)}$

Answer 1

1/{(x-1)(x+1)} = 2/{2(x-1)(x+1)}
                     = {(x+1)-(x-1)}/{2(x-1)(x+1)} = 1/2(x-1) - 1/2(x+1)