As we know
how to integrate polynomials, the integration of any rational function is reduced to the
integration of a proper rational function The rational functions which we shall consider
here for integration purposes will be those whose denominators can be factorised into
linear and quadratic factors Assume that we want to evaluate 
P( )
Q( )
∫xx dx
, where P( )
Q( )
x
x
is proper rational function It is always possible to write the integrand as a sum of
simpler rational functions by a method called partial fraction decomposition