Apart gives the partial fraction decomposition of a rational expression.
Apart[expr, var] writes expr as a polynomial in var together with a sum of ratios of polynomials, where the degree in var of each numerator polynomial is less than that of the corresponding denominator polynomial.
Apart[expr, Trig->True] treats trigonometric functions as rational functions of exponentials, and manipulates them accordingly.
Apart automatically threads over lists in expr, as well as equations, inequalities and logic functions.
EXAMPLES
Basic Examples 
Scope 