Re: Differential equation with several variables in the function

*To*: mathgroup at smc.vnet.net*Subject*: [mg97273] Re: Differential equation with several variables in the function*From*: dh <dh at metrohm.com>*Date*: Mon, 9 Mar 2009 05:18:46 -0500 (EST)*References*: <goqpau$lqg$1@smc.vnet.net>

Hi, you must try to formulate your problem as simply a s possible. If your consider f[x+y] then you should introduce a new variable z=x+y and formulate your problem in terms of the one variable function f[z]. If you would give a simple example of your problem, you may get more specific answers. hope this helps, Daniel petterbe at gmail.com wrote: > Hi, > I have a differential equation were the function F[.] depends on > several varibles,x,y,z. I would like to solve the differential > equation for the entire function. However, I only manage to get > solutions from Mathematica if I have one variable in the function. For > example DSolve[egn==0, F[x],x]. If i try to solve for my entire > function F[x+y+z] using DSolve[egn==0, F[x+y+z],x] or even just add 1 > to the function (F[x+1]) I get the error message "DSolve::litarg: To > avoid possible ambiguity, the arguments of the dependent variable in > XXX should literally match the independent variables." > > Does anybody have some good suggestions? > Thanks >