JavaScript Math asin()

let value = Math.asin(1);
console.log(value); 

// Output: 1.5707963267948966

asin() Syntax

The syntax of the Math.asin() method is:

Math.asin(angle)

Here, asin() is a static method. Hence, we are accessing the method using the class name, Math.

asin() Parameter

The asin() method takes a single parameter:

• angle - in radians whose arcsine is to be calculated

Note: The value of angle should be between -1 and 1.

asin() Return Value

The asin() method returns:

• arcsine value of the angle
• NaN (Not a Number) if the argument is either non-numeric or greater than 1 or less than -1

Example 1: Math.asin() with argument between -1 and 1

// arcsine of negative number
let number1 = Math.asin(-1);
console.log(number1); 

// arcsine of positive number
let number2 = Math.asin(0.5);
console.log(number2);

// Output:
// -1.5707963267948966
// 0.5235987755982989

In the above example, the Math.asin() method computes the arcsine of

• -1 (negative number) - results in -1.5707963267948966
• 0.5 (positive number) - results in 0.5235987755982989

Example 2 : Math.asin() for other Argument not in the range -1 and 1

// argument less than -1
let number1 = Math.asin(-100);
console.log(number1);
// Output: NaN

// argument greater than 1
let number2= Math.asin(32)
;
console.log(number2);
// Output: NaN    

Here, we get NaN as output because both the arguments, -100 and 32, are not in the range -1 and 1.

Example 3: Math.asin() with Non-Numeric Argument

let string = "Harry";

// asin() with a string argument
let value = Math.asin(string);
console.log(value); 

// Output:
// NaN

In the above example, we have tried to calculate the arcsine of the string "Harry". That's why we get NaN as the output.

Recommended readings:

• JavaScript Math sin()
• JavaScript Math acos()
• JavaScript Math atan()