Evaluate the following indefinite integrals:

(a) $\int \frac 1{(x+1)(x+2)}dx =$ + $C$.

(b) $\int \frac 1{x^4 - 1} dx =$ + $C$.

(c) $\int \frac{x}{(x+1)^2(x+2)^2} dx =$ + $C$.

(Note: Look at the page for hyperbolic functions available in WeBWorK .)