I'm trying to graph a first order differential equation in Mathematica but the graph doesn't seem right when compared to my txt book. I'm using NDSolve.
The first order diff-eq is...
dy/dt' = -cy-sin(x)+fcos(z)
where z = omega t'
c = 0.05
f = 0.4
omega = 0.7
Time t' is the x-axis
and dx/dt' is the y-axis
I have...
s = NDSolve[{\[Omega] x'[z] ==
y[z], \[Omega] y'[z] == -c y[z] - Sin[x[z]] + f Cos[z],
y[0] == -1, x[0] == 0}, {x, y}, {z, 0, 30}]
Plot[Evaluate[y[z] /. s], {z, 0, 30}, PlotRange -> All]
the graph should look akin to a cos function but the peaks are off compared to what's in my txt book.
Any ideas?