HP-71B Enhanced Math LEX

[Albert Chan]

(01-10-2020 05:40 PM)J-F Garnier Wrote:  Trig/hyperb/log/exp functions with complex arguments always use radians as unit.

Thanks for clearing this up. Sorry for the noise.

This equivalent cubic solver use identity: sin(3z) = 3 sin(z) - 4 sin(z)^3

Code:

10 DESTROY ALL @ COMPLEX A,B,C,D,E,F,G,H,K
20 INPUT "A,B,C,D ? ";A,B,C,D
30 E=3*A @ H=-B/E
40 E=((E*H+2*B)*H+C)/A
50 F=(((A*H+B)*H+C)*H+D)/A
60 K=SQRT(E/-.75)
70 E=ASIN(4*F/K^3)/3 @ G=2*PI/3 @ F=E+G @ G=E-G
80 E=SIN(E) @ F=SIN(F) @ G=SIN(G)
90 DISP E*K+H @ DISP F*K+H @ DISP G*K+H