# integral.rationalfun: Integrate a rational function In rationalfun: Manipulation of Rational Functions

## Description

Calculate the integral of a rational function. See "Details".

## Usage

 ```1 2``` ```## S3 method for class 'rationalfun' integral(expr, ...) ```

## Arguments

 `expr` an object of class "rationalfun" `...` not used in this function

## Details

The returned value is a function call with argument named "x". That is, the integral is an expression in R with an explicit form, which could be evaluated directly by calling `eval()`, or indirectly using the `int2fun()` function.

The algorithm is based on the Hermite-Ostrogradski formula which is discussed in the reference. See the article for more details.

## Value

A function call representing the explicit form of the integral.

## References

T. N. Subramaniam, and Donald E. G. Malm, How to Integrate Rational Functions, The American Mathematical Monthly, Vol. 99, No.8 (1992), 762-772.

## See Also

`integral.polynomial`

## Examples

 ```1 2 3 4 5 6 7 8``` ```# (x + 1) / (x^2 + x + 1) r <- rationalfun(c(1, 1), c(1, 1, 1)) expr <- integral(r) # Evaluate the call directly eval(expr, list(x = 2)) # Use int2fun() f <- int2fun(expr) f(2) ```

rationalfun documentation built on May 2, 2019, 10:59 a.m.