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i am new to matlab. I am trying to solve implicit equation in matlab using fsolve and and fzero command but getting error. Please guide

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syms x, L % x and L both are variables
detr=2*x*cos(L*x) - x - x*cos(L*x)^2 - x*sin(L*x)^2 + L*x^2*sin(L*x)
sol1=fzero(detr, 0)
sol2 = fsolve(detr,0)
Error: If FUN is a MATLAB object, it must have an feval method.

Answers (1)

Walter Roberson
Walter Roberson on 1 May 2016
You cannot use fzero or fsolve for symbolic expressions. You need to use either solve or vpasolve.
You only have one equation in two variables, so there is no unique solution. There are solutions at x = 0, L = 0, x*L = 2 * Pi * (Any Integer), and x*L = RootOf(sin(Z)*Z^2+4*sin(Z)-4*Z, z) . The 2 * Pi * (Any Integer) has an infinite number of solutions, and the RootOf(sin(Z)*Z^2+4*sin(Z)-4*Z, z) has an infinite number of solutions

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