Pi/2 radians different from 90 deg?

[Joe Horn]

(12-17-2021 06:06 PM)Artur - Brasil Wrote:  

(12-13-2021 06:54 PM)Joe Horn Wrote:  ... then use CAS view, in which "tan(pi/2)" returns +/- infinity.

Interesting, but: 1/0 also gives +/- infinity ??? (I don't have the Prime).

For 1/0, Prime's Home view returns +Inf when "Intelligent Math" mode is turned on, but it returns "Error: X/0" when "Intelligent Math" mode is turned off. Prime's CAS view returns +/-infinity in exact mode, but it returns +Infinity in approximate mode. Why? I have no idea.

(12-17-2021 06:06 PM)Artur - Brasil Wrote:  When the angle aproximates 90 degrees, the tan goes to +/-infinity, but tan(90o) --> error, isn't it?

For tan(90°), Prime returns either infinity or 1.63312393532×10^16 depending on mode settings. Other HP calculators also differ in what they return for tan(90°). The HP-41 returns 9.999999999×10^99, but the HP-42S says "Out of Range". The HP-15C blinks with an overflow error. The 35S says "Invalid Data" and the 10bII+ says "OFLO". The 50g in exact mode returns unsigned infinity for tan(90) but in approximate mode it beeps and says "TAN Error: Infinite Result".

Wolfram Alpha says that tan(90°) is "complex infinity".