This page demonstrates a simple numerical integrator implemented in Javascript. It's not
meant to be production quality, rather it provides an easy to use tool for folks who
are just learning about numerical integration. It also provides a link to the same computation
performed by Wolfram|Alpha, which (I guess) is supposed to be production quality. In
addition, there is a graph that is produced immediately which provides some rough
verification. That graph is not always perfect but, then, neither is numerical integration.

Credits

The input mathematical expressions are parsed using
math.js.

Some numerical computations, including the integral itself, are performed by
numeric.js. Strictly speaking, numeric.js
does not (directly) provide a numeric integration routine. It does, however, have
a fairly general ODE solver using the
Dormand-Prince method or DOPRI. Thus, the integrator works by solving the
ODE $y'=f(x)$ with initial condition $y(a)=0$ and then evaluating the result at
$x=b$.

The graph is produced by D3 and basic DOM manipulation
is provided by jQuery.