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Re: Re: Bug of Integrate

  • To: mathgroup at smc.vnet.net
  • Subject: [mg83041] Re: [mg83019] Re: Bug of Integrate
  • From: DrMajorBob <drmajorbob at bigfoot.com>
  • Date: Thu, 8 Nov 2007 06:12:54 -0500 (EST)
  • References: <fg4dfv$6c3$1@smc.vnet.net> <fg6pse$d44$1@smc.vnet.net> <28316690.1194448168488.JavaMail.root@m35> <op.t1fg2719qu6oor@monster.gateway.2wire.net> <23757859.1194488377855.JavaMail.root@m35>
  • Reply-to: drmajorbob at bigfoot.com

I stand by the v6 results I sent before.

Bobby

On Wed, 07 Nov 2007 14:09:41 -0600, Misco Viadas <misvrne at gmail.com> wrote:

> These are my results:
>
> $Version
> 5.2 for Microsoft Windows (June 20, 2005)
>
> x[t_]:=a Cos[t];y[t_]:=a Sin[t];
>
> The length of the semicircunference is:
>
> In[]: Integrate[Sqrt[1+(y'[t]/x'[t])^2)]*x'[t],{t,0,Pi}]
> Out[]: -a*Pi
>
> The length total is:
> In[]: Integrate[Sqrt[1+(y'[t]/x'[t])^2)]*x'[t],{t,0,2Pi}]
> Out[]: 2*a*Pi
>
>
> $Version
> 6.0 for Microsoft Windows (32-bit) (June 19, 2007)
>
> x[t_]:=a Cos[t];y[t_]:=a Sin[t];
>
>
> The length of the semicircunference is:
>
> In[]: Integrate[Sqrt[1+(y'[t]/x'[t])^2)]*x'[t],{t,0,Pi}]
> Out[]: -a*Pi
>
> The length total is:
>
>
> In[]: Integrate[Sqrt[1+(y'[t]/x'[t])^2)]*x'[t],{t,0,2Pi}]
> Out[]: 0
> All my calculations  stored in my computer are false?. I have to review
> them. It means that 3000 manhours to the sea.



-- 

DrMajorBob at bigfoot.com


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