Re: Help with differential equation
- To: mathgroup at smc.vnet.net
- Subject: [mg112257] Re: Help with differential equation
- From: "Nasser M. Abbasi" <nma at 12000.org>
- Date: Tue, 7 Sep 2010 02:00:44 -0400 (EDT)
- References: <i627tc$b9$1@smc.vnet.net>
- Reply-to: nma at 12000.org
On 9/6/2010 1:14 AM, mathpavi wrote: > Dear experts, > I tried solving the following differential equation using DSolve: > > y' ' [x]+a( y' [x] ) = b( cos[y] ) > > But I got error message which asked me to provide proper arguments for > cos.. > So I changed cos[y] to cos[kx] and obtained solution... > However, I have to solve the equation by keeping cos[y] in order to > obtain a solution of relevance to my work. > Please help. > praveen > it is Cos not cos, (Mathemaica is case sensitive) and also you need to write y[x] not just y inside the Cos and need to use == not = Try: de = y''[x]+ a y'[x] == b Cos[ y[x] ] DSolve[de, y[x], x] But this is non-linear ode, may be try a numerical solution? --Nasser