It seems that Access VBA does not accept negative value for power index in programming with ^ code.
Me.ReqdSpPowerP = Round(Me.SpeedP * Me.FeedRateP * Me.ToolDiaP * Forms![PropoSetUpHeadF]![SetUpPF].Form![Ks] * (((Me.FeedRateP / Me.FluteNo) * Sin(Me.PtAngle * PI / 180)) ^ (-1 * Forms![PropoSetUpHeadF]![SetUpPF].Form![mc])) * (1 - Me.RakeAngle / 100) / Forms![PropoSetUpHeadF]![FixedFactorPF].Form![McEfficiency] / 240000, 2)
If I removed (-1*) there is no error (of course it is not my desired result).
Any suggestions to overcome this issue will be highly appreciated.