View source for Curve

There are various possibilities to display curves and plots. JSXGraph supports the following curve types which can be set by changing the property "curveType".
In many cases JSXGraph can guess the curveType from the input parameters, but sometimes the curveType has to be set explicitly.
* 'plot': function plotter
* 'parameter': parameter curves. 
* 'polar': polar curves

= Function graph=
First, we initialize the board with axes:
<source lang="javascript">
var b = JXG.JSXGraph.initBoard('jxgbox', {boundingbox: [-10, 10, 20, -10], axis: true});
</source>
<jsxgraph width="600" height="400">
var b = JXG.JSXGraph.initBoard('jxgbox', {boundingbox: [-10, 10, 20, -10], axis: true});
</jsxgraph>

As input data a function graph needs between 1 and 3 parameters:
* the term for the y-component: it can be a JavaScript function having one input parameter, or an expression in GEONExT syntax.
<source lang="javascript">
create('functiongraph', [function(x){return Math.sin(x);}, ...
</source>
* The last two parameters are optional and can contain constants or functions which determine the interval of the x-component in which the graph is shown.
If these parameters are not given, the graph is plotted from the left border to the right border.
<source lang="javascript">
create('functiongraph', [function(x){return Math.sin(x);},-Math.PI,4*Math.PI]
</source>

Together, the code looks like this:
<source lang="javascript">
b.create('functiongraph', [function(x){return Math.sin(x);},-Math.PI,2*Math.PI]);
</source>
<jsxgraph width="600" height="400" box="jxgbox2">
var b2 = JXG.JSXGraph.initBoard('jxgbox2', {boundingbox: [-10, 10, 20, -10], axis: true});
b2.create('functiongraph', [function(x){return Math.sin(x);},-Math.PI,4*Math.PI]);
</jsxgraph>

== Dynamic function graphs ==
The terms for the x-component and for the y-component can also depend on another element. This can be a JSXGraph element, but it can also be the value of a DOM element. Here, we show the sine curve sin(x) multiplied by the x-component of the point "A".
<source lang="javascript">
p = b.create('point',[1,1],{size:4,name:'A'});
b.create('functiongraph', [function(x){return p.X()*Math.sin(x);}],{dash:1});
</source>
<jsxgraph width="600" height="400" box="jxgbox4">
var b4 = JXG.JSXGraph.initBoard('jxgbox4', {boundingbox: [-10, 10, 20, -10], axis: true});
p = b4.create('point',[1,4],{size:4,name:'A'});
b4.create('functiongraph', [function(x){return p.X()*Math.sin(x);}],{dash:1});
</jsxgraph>

= Plotting data - curveType:'plot' =
If the first component of the input data consists of an data array, the curveType is set to "plot". The second parameter (the y-component) can be a data array, but it also can be a function term.
<source lang="javascript">
p = b.create('point',[1,4],{size:4,name:'A'});
var dataX = [1,2,3,4,5,6,7,8];
var dataY = [0.3,4.0,-1,2.3,7,9,8,9];
b.create('curve', [dataX,dataY],{strokeColor:'red',strokeWidth:3});
b.create('curve', [dataX,function(x){ return p.X()*Math.sin(x)*x;}],{strokeColor:'blue',strokeWidth:3,dash:1});
</source>

<jsxgraph width="600" height="400" box="jxgbox3">
var b3 = JXG.JSXGraph.initBoard('jxgbox3', {boundingbox: [-10, 10, 20, -10], axis: true});
var p3 = b3.create('point',[1,4],{size:4,name:'A'});
var dataX = [-3,1,2,3,4,5,6,7,10,12];
var dataY = [4,0.3,4.0,-1,2.3,7,1.1,-2.0,4];
b3.create('curve', [dataX,dataY],{strokeColor:'red',strokeWidth:3});
b3.create('curve', [dataX,function(x){ return p3.X()*Math.sin(x)*x;}],{strokeColor:'blue',strokeWidth:3,dash:1});
</jsxgraph>

[[Category:Examples]]
[[Category:Curves]]