# Thread Subject: resolve a differentian function

 Subject: resolve a differentian function From: X_man Date: 10 Apr, 2010 19:20:25 Message: 1 of 3 how can I resolve a second degree differential function with matlab? t=0:0.1:10 diff(x,2)=5+diff(x)-7*x x is derive by t thank you very much
 Subject: resolve a differentian function From: Greg Heath Date: 11 Apr, 2010 01:39:43 Message: 2 of 3 On Apr 10, 3:20 pm, "X_man " wrote: > how can I resolve a second degree differential function with matlab? > > t=0:0.1:10 > diff(x,2)=5+diff(x)-7*x > > x is derive by t > > thank you very much 1. If t = 0:dt:tmax, then derivative approximations would be diff(x)/dt and diff(x,2)/(dt^2) 2. Given initial conditions x(1) and x(2) (or x(2)-x(1)), the equation is easily rearrange into a recursion for x(i+2). 3. However, given boundary conditions at both ends requires help from another poster or a search in the ODE documentation. 4. Finally, you can probably use the Symbolic Toolbox. Not much help, but it's a start. Greg
 Subject: resolve a differentian function From: Roger Stafford Date: 11 Apr, 2010 06:12:03 Message: 3 of 3 "X_man " wrote in message ... > ........ > diff(x,2)=5+diff(x)-7*x > ........ -----------------   It should be pointed out that this is a linear differential equation of the second order and possesses a rather elementary general solution which you can work out with paper and pen about as easily as setting matlab to do it. If nothing else this can serve as a check against the solution found by matlab. Roger Stafford

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