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Java - Math.tan() method example

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halfera

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Math.tan() is a static method that takes only one parameter and returns the approximated value of the tangent mathematical function.

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public class MathExample {
​
    public static void main(String[] args) {
        System.out.println( Math.tan( 0                  ) ); //     0 <-    0 degrees
        System.out.println( Math.tan( 0.7853981633974483 ) ); //    ~1 <-  ~45 degrees ==  PI / 4
        System.out.println( Math.tan( 1.5707963267948966 ) ); // ~+Inf <-  ~90 degrees ==  PI / 2
​
        System.out.println( Math.tan(-0.7853981633974483 ) ); //   ~-1 <- ~-45 degrees == -PI / 4
        System.out.println( Math.tan(-1.5707963267948966 ) ); // ~-Inf <- ~-90 degrees == -PI / 2
    }
}

Note: 0.9999999999999999, 16331239353195370, -0.9999999999999999 and -16331239353195370 should be equal to 1, +Inf, -1 and -Inf but they are not because of compuptation precision error.

1. Documentation

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Syntax	xxxxxxxxxx 1 package java.lang; 2 3 public final class Math { 4 5 public static double tan(double number) { ... } 6 7 } Note: Classes in the `java.lang` package are imported automatically, so it is not necessary to do it manually - we use just `Math.tan()` call.
Parameters	`number` - double value in radians (primitive value).
Result	`number` value calculated as `tan(x)` mathematical function (primitive value).
Description	`Math.tan()` is a static method that takes only one parameter and returns the approximated value of tangent mathematical function.

2. Working with radians

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public class MathExample {
​
    public static void main(String[] args) {
        double x1 = 0.0;          // beginning of calculation in radians
        double x2 = Math.PI / 2;  // ending of calculation radians
​
        double dx = Math.PI / 9; // calculation step in degrees
​
        for (double rad = x1; rad <= x2; rad += dx) {
            double y = Math.tan(rad);
​
            System.out.println("tan(" + rad + " rad) = " + y);
        }
    }
}

Output:

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tan(0.0 rad) = 0.0
tan(0.3490658503988659 rad) = 0.36397023426620234
tan(0.6981317007977318 rad) = 0.8390996311772799
tan(1.0471975511965976 rad) = 1.7320508075688767
tan(1.3962634015954636 rad) = 5.671281819617707

3. Working with degrees

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public class MathExample {
​
    static double calculateTan(double deg) {
        double radians = (Math.PI / 180) * deg;
​
        return Math.tan(radians);
    }
​
    public static void main(String[] args) {
        // Example:
        double x1 = 0.0;  // beginning of calculation in degrees
        double x2 = 90.0; // ending of calculation degrees
​
        double dx = 30.0;  // calculation step in degrees
​
        for (double deg = x1; deg  <= x2; deg  += dx) {
            double y = calculateTan(deg );
​
            System.out.println("tan(" + deg + " deg) = " + y);
        }
    }
}

Output:

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tan(0.0 deg) = 0.0
tan(30.0 deg) = 0.5773502691896257
tan(60.0 deg) = 1.7320508075688767
tan(90.0 deg) = 1.633123935319537E16

4. Reversed console plot example

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public class CustomMath {
​
    static void printLine(double y1, double y2, double dy, char character) {
        StringBuilder line = new StringBuilder("");
​
        for (double y = y1; y < y2; y += dy) {
            line.append(" ");
        }
​
        System.out.println(line.append(character));
    }
​
    public static void main(String[] args) {
        System.out.println();
        double x1 = -3.14 * 2; // begining of sine chart
        double x2 = +3.14 * 2; // end of sine chart
​
        double y1 = -4.0;
        double y2 = +4.0;
​
        double xSteps = 60;
        double ySteps = 60;
​
        double dx = (x2 - x1) / xSteps; // x axis step
        double dy = (y2 - y1) / ySteps; // y axis step
​
        for (double rad = x1; rad < x2; rad += dx) {
            double y = Math.tan(rad);
​
            if (y <= y1 || y >= y2) {
                System.out.println(" ");
            } else {
                printLine(y1, y, dy, 'x');
            }
        }
    }
}

Output: