sine of an angle in degree mode

[Thomas Okken]

(01-24-2018 10:25 AM)emece67 Wrote:  

(01-24-2018 10:04 AM)rflesch Wrote:  If there is a lookup table, pi/2 etc. could be included as well.
sine(pi) is treated differently from sine(180), on the 15C at least.

The 15C does not manage the sin(pi) case. At most it manages the sin(3.141592654) case.

I don't have a 15C handy to check, but for what it's worth, on the HP-41, sin(3.141592654) returns -4.1e-10, which indicates that it reduces the argument using a 12-digit approximation of pi (*). In fact, the sequence PI SIN is a good way to find out how many digits of pi a calculator uses for angle reduction in radians.

If PI SIN returns 0, you're either using CAS or the internal version of pi has the same number of digits as the PI function on the keyboard.

(*) Or 13-digit, which would lead to the same result: -4.10e-10 vs. -4.1e-10.