MATLAB: MATLAB gives me this warning

fzero

Check function or try again with a different starting value. Exiting fzero: aborting search for an interval containing a sign change because NaN or Inf function value encountered during search. (Function value at 2.96273e+152 is -Inf.)
MATLAB gives me this warning on command window, but it still does calculations corretly after this warning. Is this an error? I have seen this warning for first time.
Thanks

Best Answer

You are trying to find a zero of a function. This means Matlab will look for an x-value where the sign changes. During this proces it encountered a -inf value, after which it broke off its search.
What you need to do is written in the warning message: either check if your function is indeed the function you ment (i.e. check for typos), or adjust the starting value. If you have the function y=x and you start looking a x=100 and only increasing x, you'll never find the crossing. Apparently something equivalent has happened here.
Your Matlab is not broken, it just did not find the result it was looking for.
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