FWD: re: TI-92 with 'e' bug
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This is a message that I received during email correspondence with TI about
the infamous 'e' bug in the TI-92. If anyone has actually gotten a
replacement calculator (or ROM) for having the bug, please reply via
personal email, because I have tried, on several occasions, and failed.
I will be searching the digests for the email address of the original poster
of the suggestion that a replacement calculator was possible...
>Return-Path: tdonahue@ti.com
>To: "P. Kolbus" <ae607@detroit.freenet.org>
>From: "Terri D. Donahue" <tdonahue@ti.com>
>Subject: re: TI-92 with 'e' bug
>Date: Wed, 18 Sep 1996 12:20:55 -0700
>X-BeyondMail-Priority: 1
>Conversation-Id: <2.2.16.19960917152754.5aa76ed2@204.29.212.10>
>Reply-To: "Terri D. Donahue" <tdonahue@ti.com>
>X-Receipt-From-Agent: true
>
>The answer that you are receiving is the correct answer. Here is an
>explanation of why the TI-92 does this.
>
>The goals of default simplification are to insure that critical cancellations
>occur, without unnecessarily applying drastic transformations that might
>consume an unacceptable amount of time or exhaust memory. Simplification is
>necessarily a compromise between these conflicting goals.
>
>Minor appearing differences between expressions can cause dramatic differences
>in the default simplification path. For example, there is an effort to retain
>most polynomial factoring, but adding a term to a factored polynomial can cause
>the polynomial to be expanded. Similarly, there is an effort to avoid common
>denominators, unless denominators share a common factor, so some fractions
>combine while others don't. As another example, x orders more main than y, so
>merely changing the names of variables can affect how much expansion and common
>denominators occurs.
>
>Also, the default simplification path can depend strongly on the mode settings.
>
>There are so many potentially useful mathematical transformations that it is
>not feasible to fit them all in the limited amount of program ROM.
>Consequently, a useful transformation that you desire might not be in the
>TI-92. For example, x*x^n will not simplify to x^(n+1) because this is not
>one of the rules built in. Another example is integral(x^(n-1),x) will
>simplify to x^n/n, but integral(x^(n+1),x) will not simplify.
>
>Best Regards,
>Terri
>
>------------------
>Original text
>
>From: "P. Kolbus" <ae607@detroit.freenet.org>, on 9/17/96 3:27 PM:
>To: "Terri D. Donahue" <tdonahue@ti.com>
>
>I am expecting either 2^(a+b) (no simplification) or 2^a + 2^b.
>What I DON'T want is the introduction of \e\ and ln(2) into the result.
>
>In addition, I've found that this occurs only when I have a constant in the
>base. If I enter c^(a+b) with nothing defined for any of the variables, I
>get exactly what I input: c^(a+b).
>
>
>At 09:07 9/17/96 -0700, you wrote:
>>Mr. Kolbus,
>>
>>Thank you for your recent correspondence. What answers are you expecting in
>>response to these problems? Please respond directly to me.
>>
>>If I can be of further assistance, feel free to contact me again.
>>
>>Best Regards,
>>
>>Terri
>>------------------------------------------------------------
>>TI Consumer Relations Internet:ti-cares@ti.com
>>Texas Instruments Phone:(817)774-6827
>>P.O. Box 6118 m/s 3268 Fax:(817)774-6074
>>Temple, TX 76503
>>------------------------------------------------------------
>>
>>------------------
>>Original text
>>
>>From: "P. Kolbus" <ae607@detroit.freenet.org>, on 9/12/96 4:20 AM:
>>To: ti-cares@ti.com
>>
>>I have a TI-92 (recently purchased) and was playing around with some of the
>>symbolic evaluation features. I discovered something unusual:
>>
>>2^(a+b) yields e^(ln(2)*(b+a))
>>
>>2^(a+b+c) yields 2^c*e^(ln(2)*(b+a))
>>
>>2^(a-b) yields e^(ln(2)*(-b+a))
>>
>>Similar expressions yield similar results...
>>
>>My ROM version ([F5] [diamond] [(]) is 1.7 (1/18/96) and the serial number
>>is V0900085 I-0496. The 'test access' located below the lithium battery
>>(which I suspect is the ROM) has a sticker reading 'I0496-J'.
>>
>>
>+--------------------------------------------------------+
>| Peter Kolbus +1.810.474.0872 |
>| ae607@detroit.freenet.org #include <disclaimer.h> |
>+--------------------------------------------------------+
>| Due to financial problems, the light at the end of |
>| the tunnel has been permanently disconnected. |
>| |
>| Who is General Failure, and who gave him permission |
>| to read drive C? |
>| |
>| ***Written using 100% recycled electrons*** |
>| *** (70% post-consumer) *** |
>+--------------------------------------------------------+
>
>
>
>
>
+--------------------------------------------------------+
| Peter Kolbus +1.810.474.0872 |
| ae607@detroit.freenet.org #include <disclaimer.h> |
+--------------------------------------------------------+
| Due to financial problems, the light at the end of |
| the tunnel has been permanently disconnected. |
| |
| Who is General Failure, and who gave him permission |
| to read drive C? |
| |
| ***Written using 100% recycled electrons*** |
| *** (70% post-consumer) *** |
+--------------------------------------------------------+
References: