Re: Forcing functions
- To: mathgroup at smc.vnet.net
- Subject: [mg51042] Re: Forcing functions
- From: "David W. Cantrell" <DWCantrell at sigmaxi.org>
- Date: Sat, 2 Oct 2004 03:18:40 -0400 (EDT)
- Organization: NewsReader.Com Subscriber
- References: <200302110942.EAA26084@smc.vnet.net> <b2d1cl$eaa$1@smc.vnet.net> <cjj7b4$bo4$1@smc.vnet.net>
- Sender: owner-wri-mathgroup at wolfram.com
Barry Tesman <tesman at dickinson.edu> wrote:
> Can you "force" Mathematica to not use certain functions? E.g., I
> want to give my students some problems to antidifferentiate. One
> such problem is:
>
> Integrate[ x * Sqrt[x^2 + 2x +4], x]
>
> The answer uses arcsinh. Can one force Mathematica to use natural
> log instead?
Perhaps what you want is
TrigToExp[Integrate[x*Sqrt[x^2 + 2*x + 4], x]]
(1/6)*(Sqrt[4 + 2*x + x^2]*(5 + x + 2*x^2)
- 9*Log[(1 + x)/Sqrt[3] + Sqrt[1 + (1/3)*(1 + x)^2]])
David Cantrell