Question: Is it possible to change a setting, property, etc in Swift for iOS so that it assumes degrees for trigonometry calculations rather than radians?

For example `sin(90)` would be evaluated to `1`.

I have:

```
let pi = 3.14 
var r2d = 180.0/pi
var d2r = pi/180

```

... but the conversions are getting really involved for some of the long trig equations.

Answer: 
Adding an extension to identify the kind of value clearly would be a appropriate way to handle such a thing:

```
import Darwin // needed to get M_PI
extension Double {
  public var degrees: Double { return self * M_PI / 180 }
  public var ㎭: Double { return self * 180 / M_PI }
}

```

Pop that into a playground and see how you get the results you expect:

```
sin(90.degrees)  --> 1.0
1.㎭  -->  57.2957795130823
1.㎭.degrees --> 1.0
(M_PI / 3).㎭  -->  60.0

```
Seeing as I use trig a lot. I found the best way was to define some functions outside of the `class ViewController`. 

If you define them in any one of your .swift files just below the `imports` and just above the `class ViewController:UIViewController { }` then you can call them throughout the whole project.

So for the sin function, I named it `sindeg()` standing for "sin degrees".

```
func sindeg(degrees: Double) -> Double {
    return sin(degrees * M_PI / 180.0)
    }

```

So this takes your degrees number converts it, solves it and returns as degrees.
So all you need to do is type `sindeg(45.5)` and the result would = `0.71325045.`

Here is the others:

```
func cosdeg(degrees: Double) -> Double {
    return cos(degrees * M_PI / 180.0)
}
func tandeg(degrees: Double) -> Double {
    return tan(degrees * M_PI / 180.0)
}

```

arcTan here is very similar, only difference is the return formula

```
 func atanDegree(degrees: Double) -> Double {
        return atan(degrees) * 180 / M_PI
    }

```

This one is just to convert a radian value to degrees. Takes in radians, converts, returns back degrees.

```
func Convert(radians: Double) -> Double {
    return radians * 180.0 / M_PI
}

```