Trigonometric math functions

In Java, there are the following mathematical trigonometric functions:

public class TrigonometricFunctions {
	public static void main(String[] args) {
		double pi, sin, cos, tan, asin, acos, atan, rad, deg;
		
		// The double value that is closer than any other to pi, 
		// the ratio of the circumference of a circle to its diameter.
		pi = Math.PI;
		// Returns the trigonometric sine of an angle. 
		sin = Math.sin(pi);
		// Returns the trigonometric cosine of an angle.
		cos = Math.cos(pi);
		// Returns the trigonometric tangent of an angle
		tan = Math.tan(pi);
		// Returns the arc sine of a value. 
		// the returned angle is in the range -pi/2 through pi/2.
		asin = Math.asin(1.0);
		// Returns the arc cosine of a value.
		// the returned angle is in the range 0.0 through pi.
		acos = Math.acos(0);
		// Returns the arc tangent of a value.
		// the returned angle is in the range -pi/2 through pi/2.
		atan = Math.atan(1.0);
		// Converts an angle measured in degrees to an approximately equivalent angle measured in radians. 
		// The conversion from degrees to radians is generally inexact.
		rad = Math.toRadians(90);
		// Converts an angle measured in radians to an approximately equivalent angle measured in degrees. 
	    // The conversion from radians to degrees is generally inexact.
		// users should not expect cos(toRadians(90.0)) to exactly equal 0.0.
		deg = Math.toDegrees(1.5707963267948966);

		System.out.println("PI: " +  pi);
		System.out.println("sin: " +  sin);
		System.out.println("cos: " +  cos);
		System.out.println("tan: " +  tan);
		System.out.println("asin: " +  asin);
		System.out.println("acos: " +  acos);
		System.out.println("atan: " +  atan);
		System.out.println("rad: " +  rad);
		System.out.println("deg: " +  deg);
	}
}

Output

PI: 3.141592653589793
sin: 1.2246467991473532E-16
cos: -1.0
tan: -1.2246467991473532E-16
asin: 1.5707963267948966
acos: 1.5707963267948966
atan: 0.7853981633974483
rad: 1.5707963267948966
deg: 90.0