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# Java - Math.sin() method example

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`Math` `sin` is a static method that takes only one parameter and returns an approximation of sine mathematical function.

``````public class MathExample {

public static void main(String[] args) {
System.out.println( Math.sin( 0                  ) ); //   0 <-     0 degrees
System.out.println( Math.sin( 1.5707963267948966 ) ); //  ~1 <-  ~90 degrees ==  PI / 2
System.out.println( Math.sin( 3.1415926535897932 ) ); //  ~0 <- ~180 degrees ==  PI
System.out.println( Math.sin( 4.71238898038469   ) ); // ~-1 <- ~270 degrees == -PI * (3/2)
System.out.println( Math.sin( 6.2831853071795850 ) ); //  ~0 <- ~360 degrees ==  PI * 2

System.out.println( Math.sin(-1.5707963267948966 ) ); // ~-1 <- ~-90 degrees == -PI / 2
}
}``````

Note: `1.2246467991473532e-16` and `-1.133107779529596e-15` should be equal to `0` but they are not because of compuptation precision error.

## 1. Documentation

 Syntax ``````package java.lang; public final class Math { public static double sin(double number) { ... } }`````` Note: Classes in the `java.lang` package are imported automatically, so it is not necessary to do it manually - we use just `Math.sin()` call. Parameters `number` - double value that represents an angle in radians (primitive value). Result `number` value calculated as `sin(x)` mathematical function in a range `-1` to `+1` (primitive value). If the function can not calculate it returns `NaN`. Description `sin` is a static method that takes only one parameter and returns an approximation of `sin(x)` mathematical function.

``````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

}
}
}``````

Output:

``````sin(0.0 rad) = 0.0

## 3. Working with degrees

``````public class MathExample {

static double calculateSin(double deg) {
double radians = (Math.PI / 180) * deg;
}

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 = 15.0;  // calculation step in degrees

for (double deg = x1; deg  <= x2; deg  += dx) {
double y = calculateSin(deg );
System.out.println("sin(" + deg + " deg) = " + y);
}
}
}``````

Output:

``````sin(0.0 deg) = 0.0
sin(15.0 deg) = 0.25881904510252074
sin(30.0 deg) = 0.49999999999999994
sin(45.0 deg) = 0.7071067811865475
sin(60.0 deg) = 0.8660254037844386
sin(75.0 deg) = 0.9659258262890683
sin(90.0 deg) = 1.0``````

## 4. Reversed console plot example

``````public class MathExample {

public static void main(String[] args) {
double x1 = 0.0;      // beginning of sine chart
double x2 = 2 * 3.14; // end of sine chart

double dx = 3.14 / 4.0; // x axis step
double dy = 1.0  / 5.0; // y axis step

double y1 = 0.0;
double y2 = Math.sin(rad) + 1;
StringBuilder line = new StringBuilder();
for(double y = y1; y < y2; y += dy) {
line.append(" ");
}
System.out.println(line + "+");
}
}
}``````

Output:

``````     +
+
+
+
+
+
+
+``````

## References

1. Sine - Wikipedia

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