MATLAB: How to find ALL of the positive roots of exp(-0.2*x​)*cos(2*x)​-0.15*x^2+​1

expMATLABpositive roots

I enter this into Matlab but I only receive back one of its positive roots and I know it has at least three.
syms x,
y=exp(-0.2*x)*cos(2*x)-0.15*x^2+1;
sol=solve(y)

Best Answer

It has exactly three.
The easiest way is to plot the function, observe the approximate crossings, and run a numeric solver that is constrained to each range in turn.
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