The Math Forum

Search All of the Math Forum:

Views expressed in these public forums are not endorsed by NCTM or The Math Forum.

Math Forum » Discussions » Software » comp.soft-sys.matlab

Notice: We are no longer accepting new posts, but the forums will continue to be readable.

Topic: help with fzero
Replies: 1   Last Post: Aug 3, 2008 11:55 PM

Advanced Search

Back to Topic List Back to Topic List Jump to Tree View Jump to Tree View   Messages: [ Previous | Next ]

Posts: 37
Registered: 2/15/06
help with fzero
Posted: Aug 3, 2008 7:44 AM
  Click to see the message monospaced in plain text Plain Text   Click to reply to this topic Reply

i am trying to find roots of a characteristic equation (determinant of
i know the interval within which the root lies.
but the characteristic equation also has singularities in that
when i try to find out roots of this equation with the function fzero
in matlab

>> x=fzero(@fun,0.080)

it returns with an error saying :

>> 'Exiting fzero: aborting search for an interval containing a sign change
because complex function value encountered during search.
(Function value at 0.0768 is -30.9664+1.77636e-015i.)
Check function or try again with a different starting value.'


this happens after just two iterations.

i have following questions:
1) why matlab has problem with a complex valued function?

2) Since the function value has not reached zero yet, I still
need to
search for the root. How do i skip the values where function
singular (in this case Complex) ?

any help is greatly appreciated.

Date Subject Author
Read help with fzero
Read Re: help with fzero
mike zander

Point your RSS reader here for a feed of the latest messages in this topic.

[Privacy Policy] [Terms of Use]

© The Math Forum at NCTM 1994-2018. All Rights Reserved.