Re: Integrate Result depends on symbol used
- To: mathgroup at smc.vnet.net
- Subject: [mg42868] Re: Integrate Result depends on symbol used
- From: "Bill Bertram" <wkb at ansto.gov.au>
- Date: Thu, 31 Jul 2003 01:47:54 -0400 (EDT)
- Organization: Australian Nuclear Science and Technology Organisation
- References: <bg7vj2$hi7$1@smc.vnet.net>
- Sender: owner-wri-mathgroup at wolfram.com
"Jim Hanson" <hanson at physics.auburn.edu> wrote in message news:bg7vj2$hi7$1 at smc.vnet.net... > Mathematica's ability to do a definite integral depends on the symbol > used. > Here's an example with Mathematica 5.0.0.0 on a Macintosh running OSX 10.2.6. > Note that Mathematica can do the integral with a symbol z > (which comes after the variable of integration y in the alphabet) but > can't do it with a symbol x. This seems very odd to me. Does anyone > know why this happens? > > In[1]:= Integrate[Sqrt[y - x]/(y^2 Sqrt[1 - y^2]), { y , x, 1}, > Assumptions -> {x > 0, x < 1}] > Same on a PC running Windows XP. Really amazing! If you change "y" to "w" (ie one letter before "x") in the above expression, the integral is again evaluated. Cheers, Bill