Bug for TI 89 Titanum!

il matematico

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Sep 17, 2005, 12:36:10 PM9/17/05

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I think that TI 89 Titanum has a bug vs TI 89 because Titanum
doesn't solve zeros(tg(2x)+2tg(x),x) but the TI 89 solves (in partial)
this operation. Why?

Matteo Puzzle
Italy
http://it.groups.yahoo.com/group/softwarestrumentitecnologici/
http://www.matematicamente.it/giochi/La_matematica_degli_indovinelli_3.0.pdf

Bhuvanesh

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Sep 17, 2005, 2:17:02 PM9/17/05

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il matematico wrote:
> I think that TI 89 Titanum has a bug vs TI 89 because Titanum
> doesn't solve zeros(tg(2x)+2tg(x),x) but the TI 89 solves (in partial)
> this operation. Why?

What is the definition of tg(x)?

Bhuvanesh.

Gerson W. Barbosa

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Sep 17, 2005, 3:33:08 PM9/17/05

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Hello Bhuvanesh,

'tg' is short for 'tangent' here in Brazil and, I think, in Italy too.

Regards,

Gerson.

il matematico

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Sep 17, 2005, 4:36:22 PM9/17/05

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Yes!
zeros(tan(2x)+2tan(x),x)

il matematico

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Sep 17, 2005, 4:37:00 PM9/17/05

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Yes!
zeros(tan(2x)+2tan(x),x)

Bhuvanesh

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Sep 17, 2005, 5:48:53 PM9/17/05

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Hi,

I can't reproduce this. I get 19 solutions with AMS 2.09 and AMS 3.10.
Which AMS version are you using?

Bhuvanesh.

il matematico

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Sep 17, 2005, 6:37:05 PM9/17/05

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I use TI 89 and I haven't TI 89 Titanium (I can't try to compare TI 89
Titanium with old TI 89), but some people noted this difference between
TI 89 and TI 89 Titanium for this operation:
zeros(tExpand(tan(2x)+2tan(x)),x)
They signalled this problem in inofficial italian forum for calculator:
http://it.groups.yahoo.com/group/softwarestrumentitecnologici/message/1308
I think that this people, in their TI 89 Titanium, there is the last
AMS (3.10):
http://it.groups.yahoo.com/group/softwarestrumentitecnologici/message/1322
Thank you Great Bhuvanesh!

il matematico

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Sep 17, 2005, 6:42:28 PM9/17/05

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Excuse me, the operation is: zeros(tan(2x)+2tan(x),x) not
zeros(tExpand(tan(2x)+2tan(x)),x)

crawla...@lycos.com

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Sep 17, 2005, 6:48:29 PM9/17/05

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If you use solve(tan(2*x)+2*tan(x)=0,x) it gives the solution x = 0
with a warning that other solutions may exist.

If you tExpand and then divide by sin(x), and then solve that, you'll
get all the solutions (except those that correspond to sin(x) = 0).

But, yeah, the zeroes function gives an empty set for me.

I tried it on a TI89 (not Titanium) emulator, and it also gave me an
empty set when in exact mode, though. On auto mode, it gave a set of
several numerical possibilities.

If it's an issue of an outdated OS, maybe I should upgrade, though I
can still get the answer as demonstrated above. (I'm not sure what OS
I have, but I've never upgraded it).

vlacus

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Sep 17, 2005, 7:22:17 PM9/17/05

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hello,
I use TI-89 titanium with O.S. and hardware versione 3.0;
for zeros(tg(2x)+2tg(x),x) give me x=-54.7356 and x= 0 with written
"Warning: more solution may exist".

Bob Wang

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Sep 17, 2005, 7:30:08 PM9/17/05

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Just like Bhuvanesh, I get 19 solutions for AMS 2.09 on a TI-89, and AMS
3.10 on a Voyage 200

Bob
P.S. Shouldn't this be moved to the TI-89 Forum ;-) Kevin's fluent in
Italian

il matematico

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Sep 18, 2005, 4:58:41 AM9/18/05

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But, it doesn't get a result "in exact mode" for this operation:
zeros(tan(2x)+2tan(x),x)

Bhuvanesh

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Sep 19, 2005, 11:41:50 PM9/19/05

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Right, but was there really a version that gave the exact result (i.e.
the parametrized family of solutions) without applying tExpand()?

Bhuvanesh.

L.A.

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Nov 1, 2005, 12:52:58 PM11/1/05

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il matematico , Posted to the comp.sys.hp48 group , the following :

Oh gosh I'm imagining now...

If this froup starts turning into a forum for the TI-89s,

won't the HP brass try to pick-up the ball in panic ?

If there is no money for creativity and fine tuning work,

perhaps 'Fear and Shame' will drive the corporate machine our way.

You'll LOVE your TIt (TI titanium,lol).

L.A.