Originally Posted by

**KevinShaughnessy** Hi,

I'm using j when I know some textbooks use i, I'm not sure what the difference is if there is any.

I have the question (4j^5 - 5j^4 + 2j^3 -3j^2)^2 and it's supposed to evaluate to -8j, I just don't remember how to get that answer. To me it seems that something like 4j^10 could be considered as 4j^2 since there are 5 pairs of -1 resulting from multiplying j by j, so 4j^10 would be 4(-1). That does not get me the right answer though. What is the flaw in my thinking?

Thanks!