## 15 Reputation

17 years, 111 days

## second derivative of a PDE solution...

Maple 17
ptr_mplprims.mwHello,I am trying solve  a travelling force problem with pdsolve, but I cannot obtain the second derivative of the solution. I obtained the first derivative, with help from another post (http://www.mapleprimes.com/questions/80997-Derivative-From-Numeric-PDE-Soln#comment81512). When I tried doing the same thing for the second derivative it didn't work. Any sugestions would be helpful. Thank you!!!

## ODE with events...

Maple 17
HI,is it possible to solve the ODE system (that I have uploaded) by adding events at a certain timestep, instead of reformulating the system for each step.The ODE system expresses two coupled movements y(t) and X(t). The current position of y(t) is controlled by a parameter which depends on values calculated in the previous step, while changing the sign for each step.Thank you!

## How do I solve a set of ODE's, where the...

Maple 17
Hello, I'm currently trying to solve this set of ODE's, but the way I have formulated the problem seems to be hard to process. Is there any simpler way of doing this, because it takes Maple a few minutes to solve 10 steps and I need more than a 100.Thank you in advance!l := 1.34*.75;Omega[p] := sqrt(g/l);v := .75;f[p] := .35*v^3-1.59*v^2+2.93*v;bmin := 0.157e-1;ci0 := y1(0) = 0, (D(y1))(0) = v;u0 := 0+v/Omega[p]+(-1)^0*bmin;p1 := diff(y1(t), t, t)+Omega[p]^2*(u0-y1(t)) = 0;k[1...
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