I perhaps understood where the error is hiding, but this detects an alleged bug in HP PRIME G2 (hardware version). If I ask to do this calculation by virtual calculator:

I rightly get zero (to note: the figure shows the screen of the "viitual calculator"). If, however, I perform the same operation with my HP PRIME G2 (i.e. hardware version) I get an error: +Inf. This depends on the fact that, for my G2 calculator, in "CAS" the product between a very large number for the imaginary unit "i" is interpreted as "+/- Inf", which for the calculator corresponds to an indefinite value . Is there anyone who, having an HP PRIME G2, can check if the problem is common or depends only on my calculator?