Zld Productions - 1 year ago 63

Java Question

In case the title was confusing, here is what I mean. When I use the code

`Math.tan(45);`

`Math.atan(Math.tan(45));`

How would I return the degree measure of a tangent, sine, or cosine?

Answer Source

That's where functions come in. Say we have the following function:

```
public double calculateSin(double degrees) {
return Math.sin(Math.toRadians(degrees));
}
```

The function above eliminates the formula altogether, thanks to @LouisWasserman for pointing that out. The below uses the formula.

```
public double calculateSin(double degrees) {
return Math.sin(degrees * Math.PI / 180);
}
```

This is a function that takes a parameter named degrees and returns the sine of that number in radians. This can be applied to all the other trigonometric functions. Just remember the input must be radians. To convert from degrees to radians, use the formula `r = dπ/180`

where r is radians and d is degrees. Converting from degrees to radians is this formula: `d = 180r/π`

. Some other examples:

```
public double calculateTan(double degrees) {
return Math.tan(degrees * Math.PI / 180);
}
```

Again, the above uses the formula for degree conversion to radians. Below is using builtin functions.

```
public double calculateTan(double degrees) {
return Math.tan(Math.toRandians(degrees));
}
```

You would then call it using `calculateTan(180)`

which then would return 0. All this can then be applied to Math.atan and the other inverse functions.

There is also, of course, a built in functions as shown above for radian & degree conversion, which are `Math.toDegrees(double radians)`

and `Math.toRadians(double degrees)`

For extra reference, consult the JavaDocs, the Math class is linked here.