complex number and matlab precision

Hi,

How can I interpret this number? 0.49982+3.5799e-21i

The imaginary part is very small, but exist.

I seek accurate interpretation but I am confused about whether this has something to do with matlab calculation precision or whether this is has something to do with my formula in my algorithm.

I am troubled to understand this for months now.

Thank you

Answer 1

[Star Strider]

It may be some of both. My rule when dealing with situations like this is to simply ignore the imaginary part. If you want a more objective criterion, take the difference between the real part of the complex number and the magnitude (abs) of it. I ignore the imaginary part if the difference is less than 1E-10 if I have no reason to believe the imaginary part is accurate.