Wrong limit?

06102016, 01:48 PM
Post: #1




Wrong limit?  
06102016, 02:38 PM
Post: #2




RE: Wrong limit?
If you use lim(expand(...)) it returns ½ also in the Prime
∫aL√0mic (IT9CLU) :: HP Prime 50g 41CX 71b 42s 39s 35s 12C 15C  DM42, DM41X  WP34s Prime Soft. Lib 

06102016, 03:25 PM
(This post was last modified: 06102016 03:39 PM by Arno K.)
Post: #3




RE: Wrong limit?
Well, doing it by hand I get 1/4. Ups, I used a wrong formula, 4*2^n in the middle instead of 4^(2*n).
@Salvo: expand also gives 1/4 on my Prime. @Bruno: rechecking the screenshots I saw that I used two different formulas Arno 

06102016, 03:32 PM
(This post was last modified: 06102016 03:40 PM by salvomic.)
Post: #4




RE: Wrong limit?
(06102016 03:25 PM)Arno K Wrote: Well, doing it by hand I get 1/4, so TI is wrong and HP is correct. hi Arno, I used \[ \lim_{x\to\infty}( \text{expand} (\frac{2^{4x}+4^{2x}+8^x}{4^{2x+1}})) \] With FW 10077 it should be ½, later I'll control again, however (maybe I'm wrong)... ∫aL√0mic (IT9CLU) :: HP Prime 50g 41CX 71b 42s 39s 35s 12C 15C  DM42, DM41X  WP34s Prime Soft. Lib 

06102016, 03:49 PM
Post: #5




RE: Wrong limit?
As I inserted above I used the wrong formula, so this is a bug. Imho a very serious one as one usually uses commands like "lim" to keep oneself from these computations.
Arno 

06102016, 05:01 PM
Post: #6




RE: Wrong limit?
(06102016 03:49 PM)Arno K Wrote: As I inserted above I used the wrong formula, so this is a bug. Imho a very serious one as one usually uses commands like "lim" to keep oneself from these computations. I agree with you, Arno, a serious bug, apparently so simple but very insidious. Salvo ∫aL√0mic (IT9CLU) :: HP Prime 50g 41CX 71b 42s 39s 35s 12C 15C  DM42, DM41X  WP34s Prime Soft. Lib 

06102016, 06:40 PM
Post: #7




RE: Wrong limit?
Thanks for checking. Yes, adding expand() fixes it for me, too. (also FW 10077 here)
Bruno 

06102016, 10:17 PM
Post: #8




RE: Wrong limit?  
06112016, 08:24 AM
Post: #9




RE: Wrong limit?
Fix done in source code, I will update the Xcas binaries next week.
It comes from missing simplifications between ln(8), ln(4) and ln(2) not from the limit algorithm itself. 

06112016, 09:42 AM
Post: #10




RE: Wrong limit?
(06112016 08:24 AM)parisse Wrote: Fix done in source code, I will update the Xcas binaries next week. Although I don't use this advanced mathematics much, I want to say: thank you for very fast bug fixes. Prime, 15C CE 

06122016, 08:42 AM
Post: #11




RE: Wrong limit?
(06112016 08:24 AM)parisse Wrote: Fix done in source code, I will update the Xcas binaries next week. Do the missing simplifications of ln(x), in the limit() command, effect any other commands, (those that might rely on those same simplification code blocks); or is this just a local problem within the limit command? Thanks for the quick fixes! Dale 

06162016, 07:16 AM
Post: #12




RE: Wrong limit?
A part from the bug, the first image in Bruno's post is quite funny.
I don't know if you noticed that, but the app title is in german (Erweiterte Grafiken) and the error message is in french (Fonctionne seulement en mode radians...) Menus are in german (Spch for Speichern) So you have two different languages at the same time. (three if you count the Simplify menu) How can it be? 

06162016, 09:28 AM
Post: #13




RE: Wrong limit?  
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