Euler's formula in F#

1. Create new F# application on VS2010
2. Check the references containing System.Numerics

Then edit the code like below:

open System
open System.Numerics

let euler_formula = Numerics.Complex.Exp(Numerics.Complex(0.0, -Math.PI))
printfn "%O" euler_formula

At last, launch the command prompt with F5:

(-1, -1.22460635382238E-16)

It occurs by inexactness of floating-point.