Trigonometry

Post Example
Examples in JavaScript
Compute Hypotenuse in JavaScript
by yhuang JavaScript 
console.log(Math.hypot(3, 4));
// expected output: 5

console.log(Math.hypot(5, 12));
// expected output: 13
Compute Sine in JavaScript
by yhuang JavaScript 
function getCircleY(radians, radius) {
  return Math.sin(radians) * radius;
}

console.log(getCircleY(1, 10));
// expected output: 8.414709848078965

console.log(getCircleY(2, 10));
// expected output: 9.092974268256818

console.log(getCircleY(Math.PI, 10));
// expected output: 1.2246467991473533e-15

Math.sin(0);           // 0
Math.sin(1);           // 0.8414709848078965

Math.sin(Math.PI / 2); // 1
Compute Cosine in JavaScript
by yhuang JavaScript 
function getCircleX(radians, radius) {
  return Math.cos(radians) * radius;
}

console.log(getCircleX(1, 10));
// expected output: 5.403023058681398

console.log(getCircleX(2, 10));
// expected output: -4.161468365471424

console.log(getCircleX(Math.PI, 10));
// expected output: -10

Math.cos(0);           // 1
Math.cos(1);           // 0.5403023058681398

Math.cos(Math.PI);     // -1
Math.cos(2 * Math.PI); // 1
Compute Tangent in JavaScript
by yhuang JavaScript 
function getTanFromDegrees(degrees) {
  return Math.tan(degrees * Math.PI/180);
}

console.log(getTanFromDegrees(0));
// expected output: 0

console.log(getTanFromDegrees(45));
// expected output: 0.9999999999999999

console.log(getTanFromDegrees(90));
// expected output: 16331239353195370

Math.tan(1); // 1.5574077246549023
Compute Arcsine in JavaScript
by yhuang JavaScript 
// Calculates angle of a right-angle triangle in radians
function calcAngle(opposite, hypotenuse) {
  return Math.asin(opposite / hypotenuse);
}

console.log(calcAngle(6, 10));
// expected output: 0.6435011087932844

console.log(calcAngle(5, 3));
// expected output: NaN

Math.asin(-2);  // NaN
Math.asin(-1);  // -1.5707963267948966 (-pi/2)
Math.asin(0);   // 0
Math.asin(0.5); // 0.5235987755982989
Math.asin(1);   // 1.5707963267948966 (pi/2)
Math.asin(2);   // NaN
Compute Arccosine in JavaScript
by yhuang JavaScript 
// Calculates angle of a right-angle triangle in radians
function calcAngle(adjacent, hypotenuse) {
  return Math.acos(adjacent / hypotenuse);
}

console.log(calcAngle(8, 10));
// expected output: 0.6435011087932843

console.log(calcAngle(5, 3));
// expected output: NaN

Math.acos(-2);  // NaN
Math.acos(-1);  // 3.141592653589793
Math.acos(0);   // 1.5707963267948966
Math.acos(0.5); // 1.0471975511965979
Math.acos(1);   // 0
Math.acos(2);   // NaN
Compute Arctangent in JavaScript
by yhuang JavaScript 
// Calculates angle of a right-angle triangle in radians
function calcAngle(opposite, adjacent) {
  return Math.atan(opposite / adjacent);
}

console.log(calcAngle(8, 10));
// expected output: 0.6747409422235527

console.log(calcAngle(5, 3));
// expected output: 1.0303768265243125

Math.atan(1);   // 0.7853981633974483
Math.atan(0);   // 0
Math.atan(-0);  // -0

Math.atan(Infinity);   //  1.5707963267948966
Math.atan(-Infinity);  // -1.5707963267948966

// The angle that the line [(0,0);(x,y)] forms with the x-axis in a Cartesian coordinate system
Math.atan(y / x);
Compute Arctangent of y/x in JavaScript
by yhuang JavaScript
Computes the arc tangent of y/x, using the signs of the two to determine the quadrant of the return value.
function calcAngleDegrees(x, y) {
  return Math.atan2(y, x) * 180 / Math.PI;
}

console.log(calcAngleDegrees(5, 5));
//expected output: 45

console.log(calcAngleDegrees(10, 10));
//expected output: 45

console.log(calcAngleDegrees(0, 10));
//expected output: 90

Math.atan2(90, 15); // 1.4056476493802699
Math.atan2(15, 90); // 0.16514867741462683

Math.atan2(±0, -0);               // ±PI.
Math.atan2(±0, +0);               // ±0.
Math.atan2(±0, -x);               // ±PI for x > 0.
Math.atan2(±0, x);                // ±0 for x > 0.
Math.atan2(-y, ±0);               // -PI/2 for y > 0.
Math.atan2(y, ±0);                // PI/2 for y > 0.
Math.atan2(±y, -Infinity);        // ±PI for finite y > 0.
Math.atan2(±y, +Infinity);        // ±0 for finite y > 0.
Math.atan2(±Infinity, x);         // ±PI/2 for finite x.
Math.atan2(±Infinity, -Infinity); // ±3*PI/4.
Math.atan2(±Infinity, +Infinity); // ±PI/4.
Compute Hyperbolic Sine in JavaScript
by yhuang JavaScript 
console.log(Math.sinh(0));
// expected output: 0

console.log(Math.sinh(1));
// expected output: 1.1752011936438014

console.log(Math.sinh(-1));
// expected output: -1.1752011936438014

console.log(Math.sinh(2));
// expected output: 3.626860407847019

Math.sinh(0); // 0
Math.sinh(1); // 1.1752011936438014
Compute Hyperbolic Cosine in JavaScript
by yhuang JavaScript 
console.log(Math.cosh(0));
// expected output: 1

console.log(Math.cosh(1));
// expected output: 1.543080634815244 (approximately)

console.log(Math.cosh(-1));
// expected output: 1.543080634815244 (approximately)

console.log(Math.cosh(2));
// expected output: 3.7621956910836314

Math.cosh(0);  // 1
Math.cosh(1);  // 1.5430806348152437
Math.cosh(-1); // 1.5430806348152437
Compute Hyperbolic Tangent in JavaScript
by yhuang JavaScript 
console.log(Math.tanh(-1));
// expected output: -0.7615941559557649

console.log(Math.tanh(0));
// expected output: 0

console.log(Math.tanh(Infinity));
// expected output: 1

console.log(Math.tanh(1));
// expected output: 0.7615941559557649

Math.tanh(0);        // 0
Math.tanh(Infinity); // 1
Math.tanh(1);        // 0.7615941559557649
Compute Inverse Hyperbolic Sine in JavaScript
by yhuang JavaScript 
console.log(Math.asinh(1));
// expected output: 0.881373587019543

console.log(Math.asinh(0));
// expected output: 0

console.log(Math.asinh(-1));
// expected output: -0.881373587019543

console.log(Math.asinh(2));
// expected output: 1.4436354751788103
Compute Inverse Hyperbolic Cosine in JavaScript
by yhuang JavaScript 
console.log(Math.acosh(0.999999999999));
// expected output: NaN

console.log(Math.acosh(2.5));
// expected output: 1.566799236972411

Math.acosh(-1);  // NaN
Math.acosh(0);   // NaN
Math.acosh(0.5); // NaN
Math.acosh(1);   // 0
Math.acosh(2);   // 1.3169578969248166
Compute Inverse Hyperbolic Tangent in JavaScript
by yhuang JavaScript 
console.log(Math.atanh(-1));
// expected output: -Infinity

console.log(Math.atanh(0));
// expected output: 0

console.log(Math.atanh(0.5));
// expected output: 0.549306144334055 (approximately)

console.log(Math.atanh(1));
// expected output: Infinity

Math.atanh(-2);  // NaN
Math.atanh(-1);  // -Infinity
Math.atanh(0);   // 0
Math.atanh(0.5); // 0.5493061443340548
Math.atanh(1);   // Infinity
Math.atanh(2);   // NaN