|Re: HP-15C Close to perfect|
Message #6 Posted by Tommy on 7 Aug 2011, 4:54 a.m.,
in response to message #5 by Thomas Klemm
Do you really want to make that dependant on the trigonometric mode?
No, that is the same as with SQRT(-1). All perfect in normal mode
But in C-mode I would say Yes.
In normal mode the polar conversion functions uses the x- and y-registers. But in C-mode the polar conversion functions uses the Re x and Im x registers. That means that the user must know what he is doing.
And in C-mode the HP15C quietly changes mode to RAD. I do not like when a program quietly changes anything.
My first thought was that it was impossible to handle degrees in C-mode. That it violated something fundamental.
But when I realized that it accepted values in degrees in the Im x register when using the P<->R functions but not when using e, I was starting to think. (Page 134 in Owners handbook)
Suppose You want to solve the following problem: What is the angle, in degrees, corresponding to the value of i?
Solution A using ->P, C-mode and degree–mode:
0 ENTER 1 f-I f-(i) g->P Result: 1 and f-(i) shows 90 degrees (as expected)
Solution B using Eulers formula, C-mode and degree-mode:
0 ENTER 1 f-I f-(i) g->LN Result: 0 and f-(i) shows 1,57 degrees (NOT expected) (Angle in RAD)
In my opinion, this is inconsistent.
Further more, if the user by accident enters the C-mode and makes a simple 45 ENTER TAN (in degree-mode) he will be really confused. In my opinion, that is an erroneous behavior.
If this user doesn’t find page 121 in Owners manual “Deactivating Complex Mode” , he is in big problems.