I am trying to solve a set of differential equations but keep getting an error. See message below
"NDSolveValue::ndnum: Encountered non-numerical value for a derivative at t=0"
The system that I am trying to solve is the following:
e=.16
g=.4
w=.97
I set it up as follows:
sol=NDSolveValue[{y1'[t]==y2[t],y2'[t]==-((2/L[t]) L'[t]+g L[t]) y2[t]-(1/L[t]) Sin[y1[t]],L'[t]==7 e w Sin^6[w t+9 pi/8] Cos[w t+ 9 pi/8],y1[0]==-1,y2[0]==1},y1[t],y2[t],L[t]},{t,0,30}]
ParametricPlot[{y1[t],y2[t]},{t,0,30},AxesLabel->{"y1[t]","y2[t]"}]
NDSolveValue
instead ofNDSolvevalue
. Note the capital "V". $\endgroup$ – Lukas Jun 17 '16 at 9:15L[t]
. $\endgroup$ – Mariusz Iwaniuk Jun 17 '16 at 9:18