(adsbygoogle = window.adsbygoogle || []).push({}); 1. The problem statement, all variables and given/known data

General problem--I don't know how to solve for the characteristic equation in MATLAB or Mathematica to find the solution of an equations such as

2. Relevant equations

cosh(x)*cos(x) = x

(I know you can re-write this equation but it's just an example)

3. The attempt at a solution

In Mathematica I tried:

In[2]:= FindRoot[cos[x]*cosh[x] == x, {x, 0}]

During evaluation of In[2]:= FindRoot::nlnum: The function value \

{0.+cos[0.] cosh[0.]} is not a list of numbers with dimensions {1} at \

{x} = {0.}. >>

Out[2]= FindRoot[cos[x] cosh[x] == x, {x, 0}]

In[4]:= Solve[cos[x]*cosh[x] == x, x]

During evaluation of In[4]:= InverseFunction::ifun: Inverse functions \

are being used. Values may be lost for multivalued inverses. >>

During evaluation of In[4]:= InverseFunction::ifun: Inverse functions \

are being used. Values may be lost for multivalued inverses. >>

During evaluation of In[4]:= Solve::tdep: The equations appear to \

involve the variables to be solved for in an essentially \

non-algebraic way. >>

Out[4]= Solve[cos[x] cosh[x] == x, x]

Is there some method of doing this in either program? I know I can get intersection points on my calculator but that defeats the purpose of using these programs.

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# Homework Help: FZERO or some method of computing the intercept points in MATLAB or Mathematica

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