# Difference between revisions of "Simple function plotter"

Plots a function together with its derivative. First, change the function term int this text box. Second, click on "Run".

<form><textarea id="input" rows=7 cols=35 wrap="off" >
function f(x) {
return Math.cos(x)*p.Y();
}
c = plot(f);
// Derivative:
g = board.algebra.D(f);
plot(g,{strokecolor:'black', dash:1});
</textarea> <br>
<input type="button" value="run" onClick="doIt()" style='margin:1em'>
<input type="button" value="clear all" onClick="board=clearAll(board)">
</form>
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]], {});

// Macro function plotter
function addCurve(board, func, atts) {
var f = board.createElement('curve', ['x', func, 'x'], atts);
return f;
}

// Simplified plotting of function
function plot(func, atts) {
if (atts==null) {
return addCurve(board, func, {strokewidth:2, curveType:'graph'});
} else {
return addCurve(board, func, atts);
}
}

// Free point
var p = board.createElement('point', [3,-4], {style:6, name:'drag me'});

// Usage of the macro
function doIt() {
eval(\$('input').value);
}

function clearAll(board) {
JXG.JSXGraph.freeBoard(board);
board = JXG.JSXGraph.initBoard('box', {originX: 250, originY: 250, unitX: 40, unitY: 20});
b1axisx = board.createElement('axis', [[0,0], [1,0]], {});
b1axisy = board.createElement('axis', [[0,0], [0,1]], {});
return board;
}