EN
JavaScript - Math.exp() method example
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points
Math.exp() is a static method that takes only one parameter and return exponential function value in the range 0 (exclusive) to +Infinity.
// ONLINE-RUNNER:browser;
console.log( Math.exp( -100 ) ); // 3.720075976020836e-44
console.log( Math.exp( -1 ) ); // 0.36787944117144233
console.log( Math.exp( 0 ) ); // 1
console.log( Math.exp( 1 ) ); // 2.718281828459045
console.log( Math.exp( 100 ) ); // 2.6881171418161356e+43
console.log( Math.exp( -Infinity ) ); // 0
console.log( Math.exp( +Infinity ) ); // Infinity
console.log( Math.exp( NaN ) ); // NaN
1. Documentation
| Syntax | Math.exp(number) |
| Parameters | number - integer or float number value (primitive value). |
| Result |
Exponential function value of a number in the range If the value can not be calculated |
| Description |
|
2. Reversed console plot example
// ONLINE-RUNNER:browser;
var x1 = -4; // beginning of sine chart
var x2 = +2.8; // end of sine chart
var y1 = -1.0;
var y2 = +10.0;
var xSteps = 25;
var ySteps = 60;
var dx = (x2 - x1) / xSteps; // x axis step
var dy = (y2 - y1) / ySteps; // y axis step
function printLine(y1, y2, character) {
var line = '';
for(var y = y1; y < y2; y += dy) {
line += ' ';
}
console.log(line + character);
}
for (var rad = x1; rad < x2; rad += dx) {
var y = Math.exp(rad);
if (y <= y1 || y >= y2) {
console.log(' ');
} else {
printLine(y1, y, '+');
}
}
3. Canvas plot example
// ONLINE-RUNNER:browser;
<!doctype html>
<html>
<head>
<style> #canvas { border: 1px solid black; } </style>
</head>
<body>
<canvas id="canvas" width="200" height="300"></canvas>
<script>
var canvas = document.querySelector('#canvas');
var context = canvas.getContext('2d');
// exponential function chart range
var x1 = -0.1;
var x2 = +5.0;
var y1 = -0.1;
var y2 = +10.0;
var dx = 0.1;
var xRange = x2 - x1;
var yRange = y2 - y1;
var yScale = 0.1;
function calculatePoint(x) {
var y = Math.exp(x) * yScale;
// chart will be reversed horizontaly because of reversed canvas pixels
var nx = (x - x1) / xRange; // normalized x
var ny = 1.0 - (y - y1) / yRange; // normalized y
var point = {
x: nx * canvas.width,
y: ny * canvas.height
};
return point;
}
console.log('x range: <' + x1 + '; ' + x2 + '>');
console.log('y range: <' + y1 + '; ' + y2 + '>');
var point = calculatePoint(x1);
context.beginPath();
context.moveTo(point.x, point.y);
for (var x = x1 + dx; x < x2; x += dx) {
point = calculatePoint(x);
context.lineTo(point.x, point.y);
}
point = calculatePoint(x2);
context.lineTo(point.x, point.y);
context.stroke();
</script>
</body>
</html>