MaplePrimes - answers and comments on Question, dsolve(ODE, y(x), options) - Error, (in dsolve) y(x) and y cannot both appear in the given ODE.

y(x), not y

longrob — Wed, 01 Jun 2011 13:54:27 Z

You need to use -y(x) not -y

replay to One Answer

visko — Wed, 01 Jun 2011 14:41:39 Z

Doesen't work I got the same error massage:

Error, (in dsolve) y(x) and y cannot both appear in the given ODE.

You mean this?: The last -y is raplaced with -y(x)

> dsolve(sys);
%;
Error, (in dsolve) y(x) and y cannot both appear in the given ODE.

longrob is correct. When y(x)

DuncanA — Wed, 01 Jun 2011 14:54:52 Z

longrob is correct. When y(x) replaces y, dsolve gives the correct answer. The problem in visko's second attempt may be something to do with using 2D math.

ode := 4*x^2*(diff(y(x), x, x))+4*x*(diff(y(x), x))-y(x)=0;
                 2 / d  / d      \\       / d      \           
              4 x  |--- |--- y(x)|| + 4 x |--- y(x)| - y(x) = 0
                   \ dx \ dx     //       \ dx     /           
ics := y(4)=2, D(y)(4)=-2;
                           y(4) = 2, D(y)(4) = -2
dsolve({ode, ics});
                                  7  (1/2)     18  
                         y(x) = - - x      + ------
                                  2           (1/2)
                                             x

---

Duncan

Thanks!

visko — Wed, 01 Jun 2011 17:00:07 Z

Thanks for your replies

Very appreciated.

It works! :)

/visko

/Have a nice day