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StrictMath atan2() Method in Java
• Last Updated : 19 Jul, 2018

The java.lang.StrictMath.atan2() is an inbuilt method in java which is used to calculate arc tangent of ordinate_val/abscissa_val in the range between -pi and pi. It returns the angle from the conversion of rectangular coordinates (abscissa_val, ordinate_val) to polar coordinates (p, angle).

• The result is the double value closest to -pi when the abscissa_val is negative zero and the ordinate_val is negative, or the abscissa_val is negative and finite and the ordinate_val is negative infinity.
• The result is the double value closest to pi/4 when both arguments are positive infinity.
• The result is NaN when either argument is NaN.
• The result is positive zero when the abscissa_val is positive zero and the ordinate_val is positive, or the abscissa_val is positive and finite and the ordinate_val is positive infinity.
• The result is negative zero when the abscissa_val is negative zero and the ordinate_val is positive, or the abscissa_val is negative and finite and the ordinate_val is positive infinity.
• The result is the double value closest to pi when the abscissa_val is positive zero and the ordinate_val is negative, or the abscissa_val is positive and finite and the ordinate_val is negative infinity.
• The result is the double value closest to pi/2 when the abscissa_val is positive and the ordinate_val is positive zero or negative zero, or the abscissa_val is positive infinity and the ordinate_val is finite.
• The result is the double value closest to -pi/2 when the abscissa_val is negative and the ordinate_val is positive zero or negative zero, or the abscissa_val is negative infinity and the ordinate_val is finite.
• The result is the double value closest to pi/4 when both arguments are positive infinity.
• The result is the double value closest to 3*pi/4 when the abscissa_val is positive infinity and the ordinate_val is negative infinity.
• The result is the double value closest to -pi/4 when the abscissa_val is negative infinity and the ordinate_val is positive infinity.
• The result is the double value closest to -3*pi/4 when both arguments are negative infinity.

Syntax :

`public static double atan2(double abscissa_val, double ordinate_val )`

Parameters: The method accepts two parameters:

• ordinate_val: This is of double type which is the ordinate.
• abscissa_val:This is of double type which is the abscissa.

Return Value: The method returns the theta component of the point (p, angle) in polar coordinates that corresponds to the point (abscissa_val,ordinate_val).

Below programs illustrate the java.lang.StrictMath.atan2() method:
Program 1:

 `// Java praogram to illustrate the``// java.lang.StrictMath.atan2()`` ` `import` `java.lang.*;`` ` `public` `class` `Geeks{`` ` `public` `static` `void` `main(String[] args) {`` ` `    ``double` `abs_val = ``0.3` `, ord_val = ``50.00``;``     ` `    ``// It returns the theta component ``    ``// in polar coordinates ``    ``double` `atan2val = StrictMath.atan2(abs_val,``                                          ``ord_val); ``    ``System.out.println(``"Arc tangent value is: "``                                        ``+atan2val);`` ` `}``}`
Output:
```Arc tangent value is: 0.00599992800155516
```

Program 2:

 `// Java praogram to illustrate the``// java.lang.StrictMath.atan2()`` ` `import` `java.lang.*;`` ` `public` `class` `Geeks{`` ` `public` `static` `void` `main(String[] args) {`` ` `    ``double` `abs_val = ``0.3` `, ord_val = -``50.00``;``     ` `    ``// It returns the theta component ``    ``// in polar coordinates `` ` `    ``double` `atan2val = StrictMath.atan2(abs_val,``                                          ``ord_val); ``    ``System.out.println(``"Arc tangent value is: "``                                        ``+atan2val);`` ` `}``}`
Output:
```Arc tangent value is: 3.135592725588238
```

Program 3:

 `// Java praogram to illustrate the``// java.lang.StrictMath.atan2()`` ` `import` `java.lang.*;`` ` `public` `class` `Geeks{`` ` `public` `static` `void` `main(String[] args) {`` ` `    ``double` `abs_val = -``0.3` `,ord_val = ``50.00``;``     ` `    ``// It returns the theta component ``    ``// in polar coordinates `` ` `    ``double` `atan2val = StrictMath.atan2(abs_val,``                                          ``ord_val); ``    ``System.out.println(``"Arc tangent value is: "``                                        ``+atan2val);`` ` `}``}`
Output:
```Arc tangent value is: -0.00599992800155516
```

Program 4:

 `// Java praogram to illustrate the``// java.lang.StrictMath.atan2()`` ` `import` `java.lang.*;`` ` `public` `class` `Geeks{`` ` `public` `static` `void` `main(String[] args) {`` ` `    ``double` `abs_val = -``0.3` `, ord_val = -``50.00``;``     ` `    ``// It returns the theta component ``    ``// in polar coordinates `` ` `    ``double` `atan2val = StrictMath.atan2(abs_val,``                                          ``ord_val); ``    ``System.out.println(``"Arc tangent value is: "``                                        ``+atan2val);`` ` `}``}`
Output:
```Arc tangent value is: -3.135592725588238
```

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