This document discusses partial fraction decompositions, which are used to integrate rational functions. It explains that a rational function P(x)/Q(x), where P and Q are polynomials, can be broken down into a sum of simpler rational formulas where the denominators are the factors of Q(x) according to the partial fraction decomposition theorem. Two methods are used to find the exact decomposition: evaluating at the roots of the least common denominator, and matching coefficients after expanding. Examples are provided to illustrate decomposing different types of rational functions.