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Java - Math.exp() method example

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Created by:

Emelia

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Math.exp() is a static method that takes only one parameter and returns exponential function value in the range 0 (exclusive) to +Infinity.

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public class MathExample {
​
    public static void main(String[] args) {
        System.out.println( Math.exp(      -100 ) ); // 3.720075976020836E-44
        System.out.println( Math.exp(        -1 ) ); // 0.36787944117144233
        System.out.println( Math.exp(         0 ) ); // 1.0
        System.out.println( Math.exp(         1 ) ); // 2.718281828459045
        System.out.println( Math.exp(       100 ) ); // 2.6881171418161356E43
​
        System.out.println( Math.exp( Double.NEGATIVE_INFINITY ) ); // 0.0
        System.out.println( Math.exp( Double.POSITIVE_INFINITY ) ); // Infinity
        System.out.println( Math.exp( Double.NaN ) ); // NaN
    }
}

1. Documentation

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Syntax	xxxxxxxxxx 1 package java.lang; 2 3 public final class Math { 4 5 public static double exp(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.exp()` call.
Parameters	`number` - double value (primitive value).
Result	Exponential function value of a number in the range `0` (exclusive) to `+Infinity` (primitive value). If the value can not be calculated `NaN` is returned.
Description	`Math.exp()` is a static method that takes only one parameter and returns exponential function value.

2. Reversed console plot example

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public class MathExample {
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    static void printLine(double y1, double y2, double dy, String character) {
        StringBuilder line = new StringBuilder();
        for (double y = y1; y < y2; y += dy) {
            line.append(" ");
        }
        System.out.println(line + character);
    }
​
    public static void main(String[] args) {
        double x1 = -4;   // beginning of sine chart
        double x2 = +2.8; // end of sine chart
​
        double y1 = -1.0;
        double y2 = +10.0;
​
        double xSteps = 25;
        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.exp(rad);
            if (y <= y1 || y >= y2) {
                System.out.println(" ");
            } else {
                printLine(y1, y, dy, "+");
            }
        }
    }
}

Output: