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Re: solve ODE help?

  • To: mathgroup at smc.vnet.net
  • Subject: [mg72134] Re: solve ODE help?
  • From: dh <dh at metrohm.ch>
  • Date: Wed, 13 Dec 2006 06:39:35 -0500 (EST)
  • References: <eljb9d$7h0$1@smc.vnet.net>


Hi learner,

write NDSolve instead of NSolve, Derivative instead of Direvative, but 

you can also use the simplier y',  and {x,xmin,xmax} instead of x.

the correct syntax is e.g.:

NDSolve[{y'[x] + y[x] Tan[x] == Sin[2x], y[0] == 2}, y, {x, 0, 1}]

Daniel



learner wrote:

>  Hi, everyone,

>  i am new to solve ode in mathematica. i am trying to solve two

> odes(not for hw :)).

> y'+ytan(x)=sin(2x)

> 

> I use: NSolve[{Direvative[1][y][x]+y Tan[x]==Sin[2x]},y,x]

> 

> and get reply saying that:

> InverseFunction::ifun: Inverse functions are being used. Values may be

> lost for multivalued inverses

> 

> {{y[x]->cot[x](sin[2x]-y'[x]}} ,

> the mathematica did not solve the equation??

> 

> Furthermore, I add condition that y==2 when x==0 by saying:

> 

> NSolve[{Direvative[1][y][x]+y Tan[x]==Sin[2x],y[0]==2},y,x]

> 

> but no help ? why?

> thanks

> 



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