# Riemann sum III

The printable version is no longer supported and may have rendering errors. Please update your browser bookmarks and please use the default browser print function instead.

Appromximate the integral of $\displaystyle{ f: R\to R, x\mapsto x^2 }$

Riemann sum type:

### The underlying JavaScript code

<form>Riemann sum type: <select id="sumtype" onChange="brd.update()">
<option value='left' selected> left
<option value='right'> right
<option value='middle'> middle
<option value='trapezoidal'> trapezoidal
<option value='simpson'> simpson
<option value='lower'> lower
<option value='upper'> upper
</select></form>

var brd = JXG.JSXGraph.initBoard('box', {axis:true, boundingbox:[-2,40,8,-5]});
var s = brd.create('slider',[[-1,30],[2,30],[3,50,500]],{name:'n',snapWidth:1});
var a = brd.create('slider',[[-1,20],[2,20],[-10,0,0]],{name:'start'});
var b = brd.create('slider',[[-1,10],[2,10],[0,6,10]],{name:'end'});
var f = function(x){ return x*x; };
var plot = brd.create('functiongraph',[f,function(){return a.Value();}, function(){return b.Value();}]);

var os = brd.create('riemannsum',[f,
function(){ return s.Value();}, function(){ return document.getElementById('sumtype').value;},
function(){return a.Value();},
function(){return b.Value();}
],
{fillColor:'#ffff00', fillOpacity:0.3});

brd.create('text',
[1,35,function(){ return 'Sum='+(JXG.Math.Numerics.riemannsum(f,s.Value(),document.getElementById('sumtype').value,a.Value(),b.Value())).toFixed(4); }]);