# Apart

Apart[expr]

rewrites a rational expression as a sum of terms with minimal denominators.

Apart[expr,var]

treats all variables other than var as constants.

# Details and Options • 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

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## Basic Examples(2)

Decompose into partial fractions:

Compute the partial fraction representation of a rational function:

## Scope(8)

### Basic Uses(6)

Decompose a rational function into partial fractions:

Apart can handle symbolic parameters:

Treat as the main variable and as a constant:

Treat as the main variable and as a constant:

Here Apart picks as the main variable and treats as a constant:

Apart can handle non-polynomial expressions:

Apart threads over equations and inequalities:

Compute the partial fraction representation when radicals are present:

Compute the partial fraction representation over the integers modulo :

Compute the partial fraction representation following common trigonometric identities:

## Options(3)

### Modulus(2)

Partial fraction decomposition over the rationals:

Partial fraction decomposition over the integers modulo 2:

### Trig(1)

Partial fraction decompositions of trigonometric expressions:

## Applications(1)

Integrals of rational expressions of polynomials are often computed by decomposing into partial fractions:

To compute the integral, first apply Apart to the rational expression:

Apply Integrate to each summand individually and sum the results: