JavaScript sin – Find Sine of Number in Radians Using Math.sin()

To find the sine of a number (in radians), we can use the JavaScript sin() function from the math module.

Math.sin(x)

In JavaScript, we can easily use trigonometric functions with the JavaScript math module. The JavaScript math module allows us to perform trigonometry easily.

With the JavaScript math module, we can find the sine of a number easily.

To find the sine of a number, in radians, we use the math sin() function.

Below is the JavaScript syntax to find the sine of a number.

Math.sin(x)

The input to the sin() function must be a numeric value. The return value will be a numeric value between -1 and 1.

console.log(Math.sin(Math.PI/3))
console.log(Math.sin(0))
console.log(Math.sin(Math.PI/2))

#Output: 
0.8660254037844386
0.0
1.0

Converting Degrees to Radians for Input into sin()

The sin() function takes a number in radians as input. If your data is in degrees, you will need to convert the values to radians.

To convert degrees to radians, we have to create our own function in JavaScript. Below is a function that will convert degrees to radians.

function degrees_to_radians(degrees) {
  return degrees * (Math.PI/180);
}

If we have a value in degrees, we can use our new function to convert the value to radians and then pass it to the sin() function.

function degrees_to_radians(degrees) {
  return degrees * (Math.PI/180);
}

console.log(Math.sin(degrees_to_radians(60)))
console.log(Math.sin(0))
console.log(Math.sin(degrees_to_radians(90)))

#Output: 
0.8660254037844386
0.0
1.0

Finding the Inverse Sine of a Number in JavaScript

The JavaScript math module also provides us trigonometric functions to find the inverses of the common trigonometric functions. The asin() function allows us to find the inverse of the sine of a number.

Below, we show that if we pass a number to sin() and then call the JavaScript asin() function, we get back the same number.

console.log(Math.asin(Math.sin(Math.PI/3)))
console.log(Math.PI/3)

#Output: 
1.0471975511965976
1.0471975511965976

Finding the Cosecant of a Number in JavaScript

To find the cosecant of a number, we can divide 1 by the sine of the number.

We can find the cosecant of a number easily with the JavaScript sin() function. You can see how to find the cosecant of a number in the following JavaScript code.

console.log(1/Math.sin(Math.PI/3))

#Output: 
1.1547005383792517

Hopefully this article has been beneficial for you to understand how to use the math sin() function in JavaScript to find the sine of a number.