StrictMath acos() Method in Java

The java.lang.StrictMath.acos() is an inbuilt method which returns cosine of a given argument and an angle. The angle which is returned within the range between 0.0 and pi. Note: If the absolute value of the argument is greater than 1 or the argument is itself a NaN then the result is also NaN. Syntax:

public static double acos(double num)

Parameters: The method accepts one parameter num which is of double type and refers the arc whose cosine is to be returned. Return Value: The method returns the arc cosine of the argument. Examples :

Input: num = 0.45 
Output: 1.1040309877476002

Input: num = 8.9
Output: NAN

Below programs illustrate the java.lang.StrictMath.acos() method: Program 1: For positive number 

The arc cosine value of 0.65 = 0.863211890069541
arc cosine value of 6.3 = NaN

Program 2: For negative number.