Re: DSolve question

*To*: mathgroup at smc.vnet.net*Subject*: [mg49155] Re: DSolve question*From*: Bill Rowe <readnewsciv at earthlink.net>*Date*: Mon, 5 Jul 2004 04:54:45 -0400 (EDT)*Sender*: owner-wri-mathgroup at wolfram.com

On 7/2/04 at 2:01 AM, jasmith at cim.mcgill.ca (James A. Smith) wrote: >Being a Mathematica novice, I'm confused by an error generated when >I modify the following differential equation example: >Input 1: DSolve[y'[x] == 2 a x, y[x], x] Output 1: {{y[x] -> a x^2 >+ C[1]}} >This is fine. But why does the following produce an error, since >all I am doing is replacing the independent "x" variable with "t" >and the dependent "y" variable with "x": >Input 2: DSolve[x'[t] == 2 a t, x[t], t] (error) DSolve::dvnoarg: >The function x appears with no arguments. DSolve[Derivative[1][y][x] == 2*a*x, y[x], x] {{y[x] -> a*x^2 + C[1]}} DSolve[Derivative[1][x][t] == 2*a*t, x[t], t] {{x[t] -> a*t^2 + C[1]}} $Version "4.2 for Mac OS X (August 22, 2002)" As you can see, it seems to work fine for me. Here, all I did was copy and paste from your post to Mathematica in a fresh session. -- To reply via email subtract one hundred and four

**Follow-Ups**:**Re: Re: DSolve question***From:*James Smith <jasmith@cim.mcgill.ca>