Re: Bug of Integrate
- To: mathgroup at smc.vnet.net
- Subject: [mg82752] Re: Bug of Integrate
- From: roland franzius <roland.franzius at uos.de>
- Date: Tue, 30 Oct 2007 03:34:56 -0500 (EST)
- Organization: Universitaet Hannover
- References: <fg4dfv$6c3$1@smc.vnet.net>
Miguel wrote:
> When I try to calculate the integral
>
> Integrate[Sqrt[1/Cos[t]^2]*3*Cos[t],{t,0,2Pi}] Mathematica 6.0.1
> yields -6*Pi.
>
> Simplifying the expresion resultrs Integrate[3,{t,0,2*Pi}] and It is
> clear that the correct solution is 6*Pi.
>
> Is a bug of Version 6.0.1?
No, my Windo*s version 6.01 yields the correct integral value 0
Integrate[3*Sign[Cos[t]],{t,0,2Pi}]
= 6 * (pi/2- pi + pi/2)
since x/sqrt(x^2) = sign(x)
--
Roland Franzius