Quite well when you realise this comes down to cos(π/2) to which the thing answers correctly: cos(π/2) = 0.
Using HiPER Calc on Android
Using HiPER Calc on Android
See here: https://www.hpmuseum.org/cgi-sys/cgiwrap/hpmuseum/archv017.c...
And you can compare to wolfram alphas result.