Copying Rob's one-liner into my system gives yet another answer:

-1+1.22464679914735e-16i

Using perl -v, my perl is "

This is perl 5, version 32, subversion 1 (v5.32.1) built for x86_64-linux-gnu-thread-multi

". Possibly different compilers or options used to build the executables. As somebody who has dealt with floating point issues, 10**(-16) in a operation return like this is frequently noise. I'd not expect perl to return exactly zero to sin(pi) and I don't get it, but 1.22464679914735e-16.

That's hinting at something, but I'm not quite sure what.

Tried (and hopefully succeeded) in fixing the formatting, so my reply isn't in my sig.