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Thu, 22 Mar 2012 21:31:18 +0000
Diferential Equations
http://www.mathworks.com/matlabcentral/newsreader/view_thread/318251#870894
mona
<br>
Hello<br>
I need to solve the following Diferential Equations using matlab <br>
<br>
(?x/?t)(t/2)(?z/?t )=0<br>
<br>
[x(?y/?t)(t/2)z(?y/?t)(1/2)yz]=(1/2)y+((?^2 y)/( ?^2 t))<br>
<br>
[x(?z/?t )(t/2)z(?z/?t)]=(((?^2 y)/( ?^2 t)))<br>
where <br>
<br>
x(0)=0; y(0)=0; z(0)=0<br>
<br>
<br>
I am not new with matlab I tried to reduce the order and Igot system of first order Diferential Equations to use ode45 but the intial condition not enough because I need <br>
x'(0);y'(0);z'(0)<br>
<br>
I tried many times to the code but Icoudnot<br>
<br>
any help please<br>
<br>
muna

Thu, 22 Mar 2012 22:18:32 +0000
Re: Diferential Equations
http://www.mathworks.com/matlabcentral/newsreader/view_thread/318251#870897
Roger Stafford
"mona " <iee2006@yahoo.com> wrote in message <jkg5n6$kc9$1@newscl01ah.mathworks.com>...<br>
> Hello<br>
> I need to solve the following Diferential Equations using matlab <br>
> <br>
> (?x/?t)(t/2)(?z/?t )=0<br>
> [x(?y/?t)(t/2)z(?y/?t)(1/2)yz]=(1/2)y+((?^2 y)/( ?^2 t))<br>
> [x(?z/?t )(t/2)z(?z/?t)]=(((?^2 y)/( ?^2 t)))<br>
> where <br>
> x(0)=0; y(0)=0; z(0)=0<br>
> <br>
> I am not new with matlab I tried to reduce the order and Igot system of first order Diferential Equations to use ode45 but the intial condition not enough because I need <br>
> x'(0);y'(0);z'(0)<br>
> .......<br>
       <br>
You will need one more initial condition to uniquely determine a solution to these equations. That is because the equations have the second derivative of y. To use 'ode45' you will have to first solve for dx/dt, dy/dt, dz/dt, and d^2y/dt^2 in four equations. Unfortunately the denominator, xt*z/2, that will be present in the equations starts out as zero, so I'm not sure 'ode45' can handle that.<br>
<br>
Roger Stafford