View source for Trigonometric functions

The well known trigonometric functions can be visualized on the circle
of radius 1. 
* <math>tan</math>: []
* <math>sec</math>: []

<jsxgraph width="600" height="600" box="box">
var brd = JXG.JSXGraph.initBoard('box', {originX: 300, originY: 300, grid:true, unitX: 100, unitY: 100});
var ax = brd.createElement('line',[[0,0],[1,0]],{visible:false});
var ay = brd.createElement('line',[[0,0],[0,1]],{visible:false});

var p0 = brd.createElement('point',[0,0],{fixed:true,visible:false});
var p1 = brd.createElement('point',[1,0],{name:'',visible:false,fixed:true});
var c = brd.createElement('circle',[p0,p1],{dash:2,strokeWidth:1,strokeOpacity:0.6});
var p2 = brd.createElement('glider',[0.4,1.0,c],{name:'',withLabel:false});
var p3 = brd.createElement('point',[function(){return p2.X();},0.0],{visible:false,name:'',withLabel:false});
var p4 = brd.createElement('point',[0.0,function(){return p2.Y();}],{visible:false,name:'',withLabel:false});

brd.createElement('line',[p0,p2],{straightFirst:false,straightLast:false,strokeColor:'black'});   // Hypotenuse
brd.createElement('line',[p2,p3],{straightFirst:false,straightLast:false,strokeColor:'red'});     // sin
brd.createElement('line',[p2,p4],{straightFirst:false,straightLast:false,strokeColor:'red'});     // cos

var t = brd.createElement('tangent',[p2],{visible:false});
var p5 = brd.createElement('point',[brd.intersectionFunc(t,ax,0)],{visible:false,name:'',withLabel:false});
var p6 = brd.createElement('point',[brd.intersectionFunc(t,ay,0)],{visible:false,name:'',withLabel:false});
brd.createElement('line',[p5,p6],{straightFirst:false,straightLast:false});                       // tan + cot

brd.createElement('line',[p0,p6],{straightFirst:false,straightLast:false,strokeColor:'green'});   // csc
brd.createElement('line',[p0,p5],{straightFirst:false,straightLast:false,strokeColor:'green'});   // sec

brd.createElement('text',[
        function(){return (p0.X()+p2.X())*0.5;},
        function(){return (p0.Y()+p2.Y())*0.5;},
        '1'],{});

brd.createElement('text',[
        function(){return (p2.X()+p4.X())*0.3;},
        function(){return (p2.Y()+p4.Y())*0.5;},
        'cos'],{});

brd.createElement('text',[
        function(){return (p2.X()+p3.X())*0.5;},
        function(){return (p2.Y()+p3.Y())*0.5;},
        'sin'],{});

brd.createElement('text',[
        function(){return 0.1+(p2.X()+p5.X())*0.5;},
        function(){return 0.1+(p2.Y()+p5.Y())*0.5;},
        'tan'],{});

brd.createElement('text',[
        function(){return 0.1+(p2.X()+p6.X())*0.5;},
        function(){return 0.1+(p2.Y()+p6.Y())*0.5;},
        'cot'],{});

brd.createElement('text',[
        function(){return -0.2+(p0.X()+p6.X())*0.5;},
        function(){return (p0.Y()+p6.Y())*0.5;},
        'csc'],{});

brd.createElement('text',[
        function(){return (p0.X()+p5.X())*0.5;},
        function(){return (p0.Y()+p5.Y())*0.5;},
        'sec'],{});
</jsxgraph>

[[Category:Examples]]
[[Category:Geometry]]
[[Category:Calculus]]