EN
JavaScript - Math.sin() method example
17 points
Math.sin() is a static method that takes only one parameter and returns an approximation of sine mathematical function.
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console.log( Math.sin( 0 ) ); // 0 <- 0 degrees2
console.log( Math.sin( 1.5707963267948966 ) ); // ~1 <- ~90 degrees == PI / 23
console.log( Math.sin( 3.1415926535897932 ) ); // ~0 <- ~180 degrees == PI4
console.log( Math.sin( 4.71238898038469 ) ); // ~-1 <- ~270 degrees == -PI * (3/2)5
console.log( Math.sin( 6.2831853071795850 ) ); // ~0 <- ~360 degrees == PI * 26
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console.log( Math.sin( -1.5707963267948966 ) ); // ~-1 <- ~-90 degrees == -PI / 2Note:
1.2246467991473532e-16and-1.133107779529596e-15should be equal to0but they are not because of compuptation precision error.
| Syntax | Math.sin(number) |
| Parameters | number - integer or float number value that represents an angle in radians (primitive value). |
| Result |
If the function can not be calculated it returns |
| Description | sin is a static method that takes only one parameter and returns an approximation of sin(x) mathematical function. |
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var x1 = 0.0; // beginning of calculation in radians2
var x2 = Math.PI / 2; // ending of calculation radians3
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var dx = Math.PI / 36; // calculation step in degrees5
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for (var rad = x1; rad <= x2; rad += dx) {7
var y = Math.sin(rad);8
console.log('sin(' + rad + ' rad) = ' + y);9
}xxxxxxxxxx1
function calculateSin(degrees) {2
var radians = (Math.PI / 180) * degrees;3
return Math.sin(radians);4
}5
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// Example:8
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var x1 = 0.0; // beginning of calculation in degrees10
var x2 = 90.0; // ending of calculation degrees11
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var dx = 5.0; // calculation step in degrees13
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for (var deg = x1; deg <= x2; deg += dx) {15
var y = calculateSin(deg);16
console.log('sin(' + deg + ' deg) = ' + y);17
}xxxxxxxxxx1
var x1 = 0.0; // beginning of sine chart2
var x2 = 6 * 3.14; // end of sine chart3
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var dx = 3.14 / 4.0; // x axis step5
var dy = 1.0 / 5.0; // y axis step6
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for (var rad = x1; rad < x2; rad += dx) {8
var y1 = 0.0;9
var y2 = Math.sin(rad) + 1;10
var line = '';11
for(var y = y1; y < y2; y += dy) {12
line += ' ';13
}14
console.log(line + '+');15
}xxxxxxxxxx1
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<html>3
<head>4
<style> #canvas { border: 1px solid black; } </style>5
</head>6
<body>7
<canvas id="canvas" width="400" height="130"></canvas>8
<script>9
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var canvas = document.querySelector('#canvas');11
var context = canvas.getContext('2d');12
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// sine chart range14
var x1 = 0; // 0 degress15
var x2 = +2 * Math.PI; // +360 degress16
var y1 = -1.0;17
var y2 = +1.0;18
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var dx = 0.1;20
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var xRange = x2 - x1;22
var yRange = y2 - y1;23
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function calculatePoint(x) {25
var y = Math.sin(x);26
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// chart will be reversed horizontaly because of reversed canvas pixels28
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var nx = (x - x1) / xRange; // normalized x30
var ny = 1.0 - (y - y1) / yRange; // normalized y31
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var point = {33
x: nx * canvas.width,34
y: ny * canvas.height35
};36
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return point;38
}39
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console.log('x range: <' + x1 + '; ' + x2 + '> // angles in radians');41
console.log('y range: <' + y1 + '; ' + y2 + '>');42
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var point = calculatePoint(x1);44
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context.beginPath();46
context.moveTo(point.x, point.y);47
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for (var x = x1 + dx; x < x2; x += dx) {49
point = calculatePoint(x);50
context.lineTo(point.x, point.y);51
}52
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point = calculatePoint(x2);54
context.lineTo(point.x, point.y);55
context.stroke();56
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</script>58
</body>59
</html>