[RE] Can someone tell me why NDsolve isn't working here?
- To: mathgroup at smc.vnet.net
- Subject: [mg45272] [RE] Can someone tell me why NDsolve isn't working here?
- From: mizrandir at hotmail.com (Mizrandir)
- Date: Sat, 27 Dec 2003 05:00:12 -0500 (EST)
- Sender: owner-wri-mathgroup at wolfram.com
A month or so ago I posted a problem I had with a system of 6 algebraic-differential equations. In case someone is interested, I did solve the problem. First of all, the equations had some minor mistakes (a wrong sign, a missing constant...). After correcting those I simplified within them until I was left with only these two equations: x''[t] = L * (\[Theta][t]^2 * Sin[\[Theta][t]] - \[Theta]''[t] * Cos[\[Theta][t]]) / 8 \[Theta]''[t] = 3 * (g * Sin[\[Theta][t]] - x''[t] * Cos[\[Theta][t]]) / 2 / L This two equations can be simplified even more (by substitution of the first one into the second one) to get one diferential equation (of \[Theta][t]). After giving a numeric value to L and g, I soved it with NDSolve and with the \[Theta][t] function it gave me, I solved for x[t] too. I didn't solve for Rx, Ry, Fx and Fy because I wasn't interested in them (they were only needed to set up the equations). miz.