From: Rene Brun <Rene.Brun_at_cern.ch>

Date: Fri, 24 Feb 2006 08:53:47 +0100 (MET)

Date: Fri, 24 Feb 2006 08:53:47 +0100 (MET)

Both answers are correct. You simply misunderstood what
TMath::DegToRad() is doing, ie pi/180

Rene Brun

On Fri, 24 Feb 2006, zaldy wrote:

*>*

*> Hi,*

*>*

*> Just want that I will be using with degree units in carrying a calculation*

*> but,*

*>*

*> What is wrong with (1) expression?*

*>*

*> ======================================================================*

*> NOTE: It seems the operation is OK because ROOT does not complain about*

*> the writing of parameter [0] in expression "cos([0]*x)".*

*> ======================================================================*

*>*

*> 1 ----WRONG*

*> root [0] TF1 * f = new TF1("f","pow(cos([0]*x),2)",0,90);*

*> root [1] f->SetParameter(0,TMath::DegToRad());*

*> root [2] cout<<"f Integral(0,90) = "<< f->Integral(0,90) << endl;*

*> f Integral(0,90) = 45 <----WRONG*

*>*

*>*

*> 2 -----CORRECT-----*

*> root [4] TF1 * f = new TF1("f","pow(cos(x),2)",0,90);*

*> root [5] cout<<"f Integral(0,90) = "<< f->Integral(0,0.5*TMath::Pi()) << endl;*

*> f Integral(0,90) = 0.785398 <----- CORRECT*

*>*

*>*

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*>*

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*>*

*>*

Received on Fri Feb 24 2006 - 08:53:56 MET

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