# Partial fractions

If we take a fraction $\dfrac{a}{b}$, and write it as the sum of two or more fractions whose denominators are factors of $b$, then we have expressed it as a set of partial fractions.

For example, if we write $\frac{1}{6} = \frac{1}{2} - \frac{1}{3}$ then $1/2$ and $-1/3$ are called partial fractions.

Similarly, we can write $\frac{3}{(x-1)(x+2)}=\frac{1}{x-1}-\frac{1}{x+2} .$