# Partial Fraction Integration

• Sep 19th 2008, 01:29 AM
ah-bee
Partial Fraction Integration
how would i integrate this: 18/((x+3)(x^2+9)) tried doing the partial fraction method on it, and i cant find the values of A and B for: A/(x+3) + B/(x^2+9)
• Sep 19th 2008, 01:57 AM
mr fantastic
Quote:

Originally Posted by ah-bee
how would i integrate this: 18/((x+3)(x^2+9)) tried doing the partial fraction method on it, and i cant find the values of A and B for: A/(x+3) + B/(x^2+9)

Since $x^2 + 9$ is an irreducible quadratic, its contribution to the partial fraction decomposition is $\frac{Bx + C}{x^2 + 9}$, NOT $\frac{B}{x^2 + 9}$.
• Sep 19th 2008, 01:59 AM
ah-bee
ahhh... i didnt know about that, thank you!