/// <summary>
/// arctan(): the inverse function of sin(), input range of (-pi/2..pi/2)
/// </summary>
/// <param name="n1">The number to find the arctangent of (-pi/2..pi/2)</param>
/// <remarks>Note that inverse trig functions are only defined within a specific range.
/// Values outside this range will return NaN, although some margin for error is assumed.
/// </remarks>
public static BigFloat Arctan(BigFloat n1)
{
BigFloat res = new BigFloat(n1);
n1.Arctan();
return n1;
}