How to calculate the square root of a number using the Math.sqrt function?

How to calculate the square root of a number using the Math.sqrt function?

In mathematical operations, finding the square root of a number is one of the common operations. In the Java language, we can use the sqrt function in the Math class to calculate the square root. This article will introduce how to use the Math.sqrt function to calculate the square root of a number and provide specific code examples.

The Math.sqrt function is a static method in Java that can accept a double type parameter and return its square root. The following is the basic syntax of the Math.sqrt function:

double Math.sqrt(double a)

where a represents the number whose square root is to be calculated, and the return value is the square root of the number.

The following is a simple sample code that demonstrates how to use the Math.sqrt function to calculate the square root of a number:

import java.text.DecimalFormat;

public class SqrtExample {
    public static void main(String[] args) {
        // 要计算平方根的数字
        double num = 9.0;

        // 计算平方根
        double sqrt = Math.sqrt(num);

        // 输出结果
        DecimalFormat format = new DecimalFormat("0.00");
        System.out.println("数字 " + num + " 的平方根为 " + format.format(sqrt));
    }
}

In the above example, we declared a double-precision floating-point variable num and assign it a value of 9.0. We then use the Math.sqrt function to calculate the square root of num and assign the result to the sqrt variable. Finally, we use the DecimalFormat class to format the result to two decimal places and output it to the console.

When we run the above code, we will get the following output:

The square root of the number 9.0 is 3.00

In addition to calculating the square root of an integer, the Math.sqrt function You can also calculate the square root of a negative number. In this case, the function will return NaN (Not a Number).

The following is a sample code that demonstrates how to calculate the square root of a negative number and handle the case where the function returns NaN:

import java.text.DecimalFormat;

public class SqrtExample {
    public static void main(String[] args) {
        // 要计算平方根的数字
        double num = -16.0;

        // 计算平方根
        double sqrt = Math.sqrt(num);

        // 判断结果是否为NaN
        if (Double.isNaN(sqrt)) {
            System.out.println("输入的数字无效！");
        } else {
            // 输出结果
            DecimalFormat format = new DecimalFormat("0.00");
            System.out.println("数字 " + num + " 的平方根为 " + format.format(sqrt));
        }
    }
}

In the above code, we declare a double-precision floating-point variable num and assign it a value of -16.0. We then use the Math.sqrt function to calculate the square root of num and assign the result to the sqrt variable. Next, we use the Double.isNaN function to determine whether the result is NaN. If so, output a prompt message; otherwise, we format the result to two decimal places and output it to the console.

When we run the above code, since the entered number is a negative number, we will get the following output:

The entered number is invalid!

In short, calculating the square root of a number is very simple using the Math.sqrt function. We just need to pass in the number to be calculated as a parameter, and then assign the returned result to a variable. It should be noted that in the case of negative numbers, the function will return NaN. We can use the Double.isNaN function to determine whether the result is NaN and handle it accordingly.

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