Question about Texas Instruments TI-89 Calculator

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Different answer two different calculators ti-81 and ti89

Hi sorry , not the brightest light in the shop when putting in this sum on my ti-81 9492 x 2 pi then 1000 / ans then *360 my ti-81 gives me the answer 6.036217816 on my ti-89 i do the same sum to get 15000/(791*pi)

please could anyone help im a bit thick

many thanks john

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I had the same problem when I got my first 89, even though it's really a feature and not a problem.

Press the diamond key then enter to get your answer, and it will give you the decimal answer instead of the exact answer like you have been getting. Hope this helps...

Posted on Dec 03, 2008

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1 Answer

Error Dimension mismatch on ti89

Error Dimension Mismatch:
Two or more arguments must be of the same dimension. For
example, [1,2]+[1,2,3] is a dimension mismatch because the
matrices contain a different number of elements.

Mar 23, 2016 | Texas Instruments TI-89 Calculator

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TI-89 incorrect answer

You're not doing anything wrong. The TI-89 simply does not reduce odd powers in square roots. If you change the 13 to 14 you'll see a rather different result.

Apr 11, 2012 | Texas Instruments TI-89 Calculator

1 Answer

@n sign on ti 89

That's because there's an infinite number of solutions to your equation. Replacing the @n with any integer gives you a new, different solution.

Mar 14, 2012 | Texas Instruments TI89 Titanium Scientific...

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TI89 is giving wrong answer for the integral of sec(x). Please help. It gives the answer as: ln[ |cos(x) / (sin(x)-1)| ] when it should be ln[ |(sin(x)-1) / cos(x)| ]. Why is it giving the wrong...

Hi danagasta,

If my last instructions did not work then you need to reset your RAM. You are missing the negative sign and, I have no idea where you got the absolute value inside the brackets.
Yes, the absolute value are used in books and, on integral tables but, I can asure you that the Ti 89 should not have produce them in this answer.

I'll stand behind that In( -cos(x) / (sin(x)-1)) is the correct answer. You can go ahead and simplify after the calculation to get the answer you want but, that is the good answer that Ti 89 is going to give you for the integral of sec(x).

Errors that do not match the suspected, I am pretty sure that Texas Instruments would have you clear the RAM. I do not like resetting the RAM but, I could not find the cause to why you got the answer you did. And so far no other expert has produced a solution to convince me otherwise.

I was not able to come up with any of the 3 answers MiB8888 did on my Ti 89. I am not saying that they are not good answers, they are book and integral tables answers. You are not going to get them on the Ti 89.

Jan 04, 2011 | Texas Instruments TI-89 Calculator

1 Answer

Ti-98 calculator

Here is the link to the TI89/Ti92PLUS calculator manual, nad here is the link to the Ti89Titanium manual.
BTW, I have no knowledge of a TI98 calculator (Must be a typographical error.)

Apr 22, 2010 | Texas Instruments TI-92 Plus Calculator

2 Answers

I received this solution, but at the end the calculator asked me about some invalid certificate. Now the ti 89 is stuck at the boot screen because if I retry, it goes thru the whole process again and asks...

The answer I gave you was taken verbatim from the TI FAQ and knowledge base. I copied and pasted the part relevant to you calculator.
In any case, I sent an e-mail message to, giving the link to your original question and my answer to it. I took the liberty to copy/paste your present message. I also asked about that invalid certificate.
All we can do know is wait for their reply.


Oct 31, 2009 | Texas Instruments TI-89 Calculator

2 Answers

How to sum series

Click on the Mode button twice until you see “SD”. Select 1. This puts the calculator in Statistics Mode. image001.gif Enter the first number, 1.
image001.gif Hit the M+. (n= 1 will appear in the window)
image001.gif Enter the second number, 1.
image001.gif Hit the M+ key. (n=2 will appear in the window)
image001.gif . . . . .
image001.gif Enter the last number, 7.
image001.gif Hit the M+ key. (n=7 will appear in the window)
image001.gif Hit shift, 2. (This invokes the S-Var option.)
image001.gif Hit 1 for the sample mean. Hit Enter.
image001.gif Hit 3 for the sample standard deviation that we will use in class. Hit Enter. here you can also ffind the sum of all numbers

Jan 21, 2009 | Casio FX-300MS Calculator

2 Answers

Different answer fro my TI-89 AND MY tI-81

Your TI81 can only perform numerical calculation: It always give uour numbers. The TI89, a more sophisticated calculator, can of course do numerical calculation, BUT ALSO symbolic ones. You ask it for the derivative of sin(x) and it will give you cos(x).
Anyway, if you want a decimal result for you calculation above one of the numbers must have a decimal point (instead of writing 2PI write 2.PI.

The TI 89 can do exact calculations. But if you want approximate results any number in the sequence of operations must have the mark of a decimal. Numbers without decimal marks are considered integers, Integer numbers with a decimal mark are treated as floating point numbers ( meaning decimal).

Hope it clarifies things for you.

Nov 15, 2008 | Texas Instruments TI-89 Calculator

4 Answers

Cube roots on ti89

The TI-89 has one function to find whatever root you want of a number.

To find the cubed root of say...64, you would type:


Sep 15, 2008 | Texas Instruments TI-89 Calculator

2 Answers

Calculator quick working

Mine did the same thing and I was told by Texas Instruments that I can send it in for repair--for $81 since it is more than 1 year old.

Feb 16, 2007 | Texas Instruments TI-89 Calculator

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