What does i mean as example: 1.2428 - 0.0003i

What is the meaning of the result i get when i run matlab code:

   1.2428 - 0.0003i
   1.2320 - 0.0003i
   1.2250 - 0.0002i
   1.2376 - 0.0003i
   1.2332 - 0.0004i

Answer 1

[Walter Roberson]

In this context i is the imaginary unit. Those are all complex numbers, such as complex(1.2428, -0.003)

[Matlaber]

Thanks.

Is that mean imaginary unit means the answer is very small?

Because i running a matlab code, the answer suppose to be integer.

[Adam]

It bears no real relation to size. How 'big' the result is is determined by

doc abs

of that complex result. In this case you are nowhere near an integer though, even if you ignore the small imaginary part, though ignoring imaginary parts in an answer you expect to be real is rarely a good idea unless you are 100% convinced they are the result of rounding errors, as most of the time getting a complex result when you expect a real one implies something is wrong in your calculation.

[Stephen23]

"Is that mean imaginary unit means the answer is very small?"

No:

https://en.wikipedia.org/wiki/Imaginary_unit

If your high-school did not teach complex numbers then you missed out on a very important mathematical concept. There are plenty of good tutorials online which introduce complex numbers.

[Walter Roberson]

If you were doing something like fsolve() or fzero() then it is possible that the system you are working with has multiple answers, some of which happen to be complex valued. If you are finding the root of an equation in a single variable, then you might need to use fzero() and pass a range of values as the second parameter to confine the search to that range.

Answer 2

[alan daniel]

Thanks