Arithmetics of complex numbers

The underlying JavaScript code

Addition:

board = JXG.JSXGraph.initBoard('box', {boundingbox: [-6, 6, 8, -4], axis: true});
        
var org = board.create('point', [0,0], {style:10,visible:true,fixed:true,name:' '});
var x = board.create('point', [2,2], {style:5,color:'blue',name:'x'});
var y = board.create('point', [-1,-3], {style:5,color:'blue',name:'y'});
var xy = board.create('point', 
    ["X(x) + X(y)", "Y(x) + Y(y)"], {style:7,color:'green',name:'x+y'});
var ax =board.create('arrow', [org, x], {strokeColor:'blue'});
var ay =board.create('arrow', [org, y], {strokeColor:'blue'});
var axy =board.create('arrow', [org, xy], {strokeColor:'red'});
var ax2 =board.create('arrow', [x, xy], {strokeColor:'blue',strokeWidth:1,dash:1});
var ay2 =board.create('arrow', [y, xy], {strokeColor:'blue',strokeWidth:1,dash:1});

Multiplication:

brd2 = JXG.JSXGraph.initBoard('box2', {boundingbox: [-6, 6, 8, -4], axis: true});
        
var org2 = brd2.create('point', [0,0], {style:10,visible:true,fixed:true,name:' '});
var x = brd2.create('point', [1,0], {style:4,color:'blue',name:'x'});
var y = brd2.create('point', [0,2], {style:4,color:'red',strokeColor:'red',name:'y'});
var xy = brd2.create('point', 
    ["X(x) * X(y) - Y(x) * Y(y)","X(x) * Y(y) + X(y) * Y(x)"], {style:7, fillColor:'green', strokeColor:'green', name:'x*y'});
var c = brd2.create('circle',[org2,1],{strokeWidth:1,dash:1});

References

• http://en.wikipedia.org/wiki/Complex_numbers