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Trigonometric Functions for the HP-38C/HP-12C
07-12-2017, 05:00 PM (This post was last modified: 07-12-2017 05:03 PM by Gerson W. Barbosa.)
Post: #16
RE: Trigonometric Functions for the HP-38C/HP-12C
(07-12-2017 03:17 PM)tiptongrange Wrote:  
(03-25-2016 04:51 AM)Gerson W. Barbosa Wrote:  Unfortunately more digits won't help here. In order to improve the accuracy you would need more constants, but then this wouldn't be possible on the HP-12C/38C using this approach, given their limited memory. I was able to get much better accuracy and functionality on the HP-12C Platinum whose 20 registers are always available, even when all 400 programming steps are fully used:


I'm wondering whether there's a mistake at the beginning of this particular program for the 12c. At line 006 x<>y, what is supposed to be in the y register? The program doesn't put anything in there, so it would be any random number that was left in the stack before the program was started.

I'm running this on a simulator and not getting results remotely close to what they should be.

This was meant to preserve the original X register. From the linked article:

2) sin²(30) + cos²(30):

Notice that the stack register X is always preserved, so there's no need to store intermediate results in 
simple chain calculations (one-level only), as in this example.  

Keystrokes                Display

30 R/S                  0.500000000
g x²                    0.250000000
30 g GTO 090 R/S        0.866025404
g x2                    0.750000000
+                       1.000000000


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RE: Trigonometric Functions for the HP-38C/HP-12C - Gerson W. Barbosa - 07-12-2017 05:00 PM

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