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Re: Indefinate integrals, erroneus Natural log?

• To: mathgroup at smc.vnet.net
• Subject: [mg77918] Re: Indefinate integrals, erroneus Natural log?
• From: dh <dh at metrohm.ch>
• Date: Tue, 19 Jun 2007 07:00:15 -0400 (EDT)
• References: <f55oor$j6f$1@smc.vnet.net>

Hi David,

note that in your input there is no space between x and E. If I put the 

space in, version 5.1 and 6 give:

E^(2*x)*(-1/4 + x/2)

hope this helps, Daniel



David Rees wrote:

> Hi,

> 

> In preparation for a major exam tomorrow, I was just checking some of my 

> answers to past-papers with mathematica, I fed it this input:

> 

> In[117]:=

> \!\(\[Integral]\((xE\^\(2 x\))\) \[DifferentialD]x\)

> Out[117]=

> \!\(xE\^\(2\ x\)\/\(2\ Log[xE]\)\)

> 

> I marked myself wrong and moved on to the next question, but I happened 

> accross the actual mark-scheme which said I was correct. It gave this 

> answer:

> 

> ((1/2)xE^(2x))-(1/4)e^(2x)

> 

> My Integral calculus isn't so strong, so I don't know if the additional 

> natural log should be there, or if the two expressions are identical.

> 

> Thanks

> 

> 

>