Integrate using partial fractions (#77)

Integrate using partial fractions (#77)

Algebraic fractions can be integrated by separating into bpartial fractions/b and integrated using the standard result:

(\displaystyle\int{\dfrac{1}{x}} dx = \ln{x} + c )

For example:

(\displaystyle\int{\dfrac{px+q}{(x+a)(x+b)}} dx = \displaystyle\int{\bigg(\dfrac{A}{x+a}+\dfrac{B}{x+b}\bigg)} dx )

(\quad = A\ln{|x+a|} + B\ln{|x+b|} + c )