Are there any methods which do that? I have an application where I need the area under the curve, and I am given the formula, so if I can do the integration on hand, I should be able to do it programatically? I can’t find the name of the method I’m referring to, but this image demonstrates it: http://www.mathwords.com/a/a_assets/area%20under%20curve%20ex1work.gif
Edit: to everyone replying, I have already implemented rectangular, trapezoidal and Simpson’s rule. However, they take like 10k+ stripes to be accurate, and should I not be able to find programatically the integrated version of a function? If not, there must be a bloody good reason for that.
Numerical integration
There are multiple methods, which can be used. For description, have a look in Numerical Recipes: The Art of Scientific Computing.
For Java there is Apace Commons library, which can be used. Integration routines are in Numerical Analysis section.
Symbolic integration
Check out jScience. Functions module “provides support for fairly simple symbolic math analysis (to solve algebraic equations, integrate, differentiate, calculate expressions, and so on)”.
If type of function is given, it can be possible to integrate faster in that specific case than when using some standard library.