Arithmetics of complex numbers

Addition of complex numbers

        board = JXG.JSXGraph.initBoard('box', {originX: 250, originY: 250, unitX: 40, unitY: 40});
        // Axes
        b1axisx = board.createElement('axis', [[0,0], [1,0]], {});
        b1axisy = board.createElement('axis', [[0,0], [0,1]], {});
        
        var org = board.createElement('point', [0,0], {style:10,visible:true,fixed:true,name:' '});
        var x = board.createElement('point', [2,2], {style:5,fillColor:'blue',name:'x'});
        var y = board.createElement('point', [-1,-3], {style:5,fillColor:'blue',name:'y'});
        var xy = board.createElement('point', 
              ["X(x)+X(y)","Y(x)+Y(y)"], {style:7,fillColor:'blue',name:'x+y'});
        var ax =board.createElement('line', [org,x], {straightFirst:false,straightLast:false,lastArrow:true,strokeColor:'blue'});
        var ay =board.createElement('line', [org,y], {straightFirst:false,straightLast:false,lastArrow:true,strokeColor:'blue'});
        var axy =board.createElement('line', [org,xy], {straightFirst:false,straightLast:false,lastArrow:true,strokeColor:'red'});
        var ax2 =board.createElement('line', [x,xy], {straightFirst:false,straightLast:false,lastArrow:true,strokeColor:'blue',strokeWidth:1,dash:1});
        var ay2 =board.createElement('line', [y,xy], {straightFirst:false,straightLast:false,lastArrow:true,strokeColor:'blue',strokeWidth:1,dash:1});