Managed implementation of various System.Math functions.

MathM.cs

static class MathM
{
    public const float PI = (float)System.Math.PI;
    public const float TwoPI = PI * 2;
    public const float HalfPI = PI * 0.5f;

    public static float Sin(float x)
    {
        float x3 = x * x * x;
        float x5 = x3 * x * x;
        float x7 = x5 * x * x;

        //              2!      3!          4!
        return x - x3 / 6 + x5 / 120 - x7 / 5040;
    }

    public static float Cos(float x)
    {
        return Sin(x + HalfPI);
    }

    public static float Tan(float x)
    {
        return Sin(x) / Cos(x);
    }

    public static float Asin(float x)
    {
        float x3 = x * x * x;
        float x5 = x3 * x * x;
        float x7 = x5 * x * x;

        //                       3 / 40        5 / 112
        return x + x3 / 6 + x5 * 0.075f + x7 * 0.044642857f;
    }

    public static float Acos(float x)
    {
        return HalfPI - Asin(x);
    }
}