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

```
I'm not entirely sure why you'd want to overload the default global method, but if you must, you can provide an alternate method signature:

```
func sin(#degrees: Double) -> Double { // Require a parameter name for method call
    let radians: Double = degrees * (M_PI / 180) // Convert to rad
    return sin(radians) // Return result of default method call with automatic conversion
}

sin(degrees: 90) // 1.0
sin(degrees: 180) // 0.0

```

However, this is really an odd way of doing it, and it would make more sense to explicitly define your own method (that's what they're for), in a similar way:

```
func sinFromDegrees(degrees: Double) -> Double {
    let radians: Double = degrees * (M_PI / 180)
    return sin(radians)
}

sinFromDegrees(90) // 1.0
sinFromDegrees(180) // 0.0

```