Function piVBA() As Double Dim pi As Double piVBA = 4 * Atn(1) End Function Function atanhVBA(X As Double) 'http://tancro.e-central.tv/grandmaster/excel/vba-function-triangle.html If X <= -1 Then atanhVBA = 0 ElseIf X >= 1 Then atanhVBA = 0 Else atanhVBA = 1 / 2 * Log((1 + X) / (1 - X)) End If End Function