Are you trying to just plot an underdamped oscillator? Or are you trying to fit beta and w0? The below script will actually fit.
Names Default to here(1);
dt = New Table("Harmonic Oscillator",
New Table Variable("beta", .3),
New Table Variable("w0", .4),
New Column("t", set values(0::50)),
New Column("Cos t", formula(Cos(t))),
New Column("Damped Cos t", Formula(
exp(-:beta*:w0*:t)*cos(:w0*t) + random normal(0, .01) //just adding noise
)),
New Column("Predictor",
Formula(
Parameter({pbeta = .2, pw0 = .5},
exp(-pbeta*pw0*:t)*cos(pw0*t)
)
)
)
);
dt << Nonlinear( Y( :Damped Cos t ), X( :Predictor ), Newton );
To give you this. notice how my actual beta/w0 was .3/.4 but I started my predictor with .2/.5
Is this sort of what your'e looking for?