HP49-50G : tan(x) 50% faster than sin(x) or cos(x)

[Eric Rechlin]

The algorithm for SIN/COS/TAN in the 48/49/50 is the following:

Code:


The absolute value of the argument is dbl word reduced 
by 2*Pi (or 360), then by Pi/2, and Pi/4 to obtain 
0<=Phi<=Pi/4.  A pseudo divide produces (X,Y) with 
0<=Y<=X and TAN(Phi) = Y/X .  Formulas;
       TAN(Phi) = Y/X
       SIN(Phi) = 1/SQRT(1+(X/Y)^2)
       COS(Phi) = 1/SQRT(1+(Y/X)^2)