I have been asked to give an example of a sequence in C (complex) which tends to zero but the principal value if the argument does not tend to a limit.

I know that one example would be Zn=(-1)*n/n for n>=1.

However i don't understand how the principal value alternates between pi and 0 for this example, or how to calculate the principal value for a complex sequence in general.

Any help wold be greatly appreciated. Thanks.