HP 48gII - Manual (Page 171)

Page 4-9
The following screen shows that functions EXPM and LNP1 do not apply to
complex numbers. However, functions GAMMA, PSI, and Psi accept complex
numbers:
Function DROITE: equation of a straight line
Function DROITE takes as argument two complex numbers, say, x
1
+iy
1
and
x
2
+iy
2
, and returns the equation of the straight line, say, y = a+bx, that
contains the points (x
1
,y
1
) and (x
2
,y
2
). For example, the line between points
A(5,-3) and B(6,2) can be found as follows (example in Algebraic mode):
Function DROITE is found in the command catalog ( ‚N).
Using EVAL(ANS(1)) simplifies the result to: