LOG for HP 12C

08302017, 01:47 AM
Post: #1




LOG for HP 12C
Here is a LOG program for HP 12C
Find the LOG in any base of any number: LOGь X: X > 0, b > 1 01 LN 02 R↓ 03 LN 04 R↓ 05 R↓ 06 R↓ 07 ÷ 08 GTO 00 Example: LOG₃ 9 = 2 9 ENTER 3 R/S 2 LOG₈₁ 3 = ⅟₄ 3 ENTER 81 R/S 0.25 LOG₁₀₀₀ 10 = ⅓ 10 ENTER 1000 R/S 0.33 Gamo 

08302017, 02:07 AM
(This post was last modified: 08302017 02:13 AM by Gerson W. Barbosa.)
Post: #2




RE: LOG for HP 12C
Here is my version. Not exactly faster, better or more accurate, only three steps shorter:
01 LN 02 1/x 03 y^x 04 LN 05 GTO 00 Best regards, Gerson.  PS: Or, in a more conventional way, but one step longer: 01 LN 02 x<>y 03 LN 04 / 05 1/x 06 GTO 00 

08302017, 02:07 AM
(This post was last modified: 08302017 02:09 AM by Gene.)
Post: #3




RE: LOG for HP 12C
EDIT: Rats, Gerson was faster and shorter. :) Is either method more accurate?
Good idea! How about: LN X<>Y LN X<>Y / GTO 00 

08302017, 02:20 AM
Post: #4




RE: LOG for HP 12C  
08302017, 04:22 AM
Post: #5




RE: LOG for HP 12C
Thanks for more alternative ways of LOG program.
Just wondering about the compute functions like 1/x or y^x will take more time to calculate than just using Rv or X<>Y Gamo 

08302017, 02:42 PM
Post: #6




RE: LOG for HP 12C
(08302017 04:22 AM)Gamo Wrote: Just wondering about the compute functions like 1/x or y^x will take more time to calculate than just using Rv or X<>Y Rv and x<>y are simple operations involving transfer of contents between internal registers. y^x alone requires a call to LN and another to e^x, both transcendental functions that take a lot a shift and add operations plus access to external tables in ROM. On slow calculators like the original HP12C the difference in speed is quite noticeable, even without a stopwatch. The choice of which solution to use depends on what amount of free memory you have. The fivestep version would make sense if those were the last remaining free steps on you 12C. Gerson. 

« Next Oldest  Next Newest »

User(s) browsing this thread: 1 Guest(s)