Question about Texas Instruments TI-89 Calculator

# Integration Whenever I try to integrate on my calculator it gives the answer as the same equation that I put in. For example, if I enter the integral of ln(1+2^x) the answer is ln(1+2^x). How do you recommend I fix this?

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The integral cannot be calculated in terms of the elementary functions. It is given by dilogarithm Li_2. Note here that log stands for the natural logarithm (ln)

Posted on Jan 02, 2014

• k24674 Jan 02, 2014

You should say: it gives the answer as the same expression I put in. Not equation, the integral is a function.

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Posted on Jan 02, 2017

Hello,
This calculator can only perform NUMERICAL DEFINITE integrals. Which meansyou have to supply the numerical value of the lower limit and the numerical value of the upper limit. The result is a numerical value.
The calculator cannot perform symbolic calculus.

If the function is simple you find the integral in tables of integrals where you will see that INT(log(X)dx=x(log(x)+1). Some calculators that have a CAS (computer algebra system) can manipulate symbolic expression, but not theCasio FX-991ES.

You ask it the value of the integral of log(X) from X=1 to X=3 and it will give you 0.5627748004

Hope it helps

Posted on Sep 06, 2009

Hello,
Clear all variables [F6] [ENTER]
Here is a screen capture of the display for your integral.

Hope it helps

Posted on Sep 13, 2009

Hello,
This means that you are using a non-algebraic variable in an expression. I know, I am not even paraphrasing. Exemple: if you write 2 + johnQ, where johnQ is a table of data, a picture or a GDB, graphical data base object.

Here is an exemple where mat is a 2X2 matrix and mot is a table.
Hope it helps.

Posted on Sep 14, 2009

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.

Posted on Jan 09, 2011

SOURCE: when i do my integration

What are you trying to do? The syntax you use depend on what you want to achieve.
Indefinite integral : Integral( ln(x),x) gives the correct answer xln(x)-x
Definite integral : Integral(ln(x),x,1,2) gives the integral of ln(x) between x=1 and x=2
Definite integral between 1 and y : Integral (ln(x), x,1,y) gives the correct expression yln(y)-y +1

By inserting the =0 you are in fact assigning the result of the integration to value 0, and the calculator calculates the integral and assigns 0 to it. This is what my TIVoyage 200 PLT gives me:
{Integral((lnx),x,1) = 0.} returns {x.ln(x)-x+1=0}
which is an equation.

Posted on Apr 28, 2011

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## Related Questions:

### Evaluating a problem using integration with sin x and cos x

4/sqroot2 is the same value as 2sqroot2, about 2.828 . It's just a matter of how the calculator and the textbook chooses to represent the value.

Dec 30, 2012 | Office Equipment & Supplies

### Error: dependent limit

Dependent limit error may occur if a limit of integration is dependent on the integration variable.

For example, integral:

int(x^2,x,1,x) is not allowed

Sep 06, 2012 | Texas Instruments TI-89 Calculator

### When i do my integration problems i am getting my answers in decimal form. for example {S((lnx),x,1) = 0.}

What are you trying to do? The syntax you use depend on what you want to achieve.
Indefinite integral : Integral( ln(x),x) gives the correct answer xln(x)-x
Definite integral : Integral(ln(x),x,1,2) gives the integral of ln(x) between x=1 and x=2
Definite integral between 1 and y : Integral (ln(x), x,1,y) gives the correct expression yln(y)-y +1

By inserting the =0 you are in fact assigning the result of the integration to value 0, and the calculator calculates the integral and assigns 0 to it. This is what my TIVoyage 200 PLT gives me:
{Integral((lnx),x,1) = 0.} returns {x.ln(x)-x+1=0}
which is an equation.

Apr 17, 2011 | Texas Instruments TI-89 Calculator

### Can the casio fx9750gplus calculator show differentiation/integration etc. for example differentiate 5x^3 and have it show 15x^2?

Sorry to disappoint you but the Casio FX-9750Gplus does not handle symbolic calculations. It does not have a Computer Algebra System or CAS. It can however calculate the numerical integration of a function between two limits, as well as the first and second derivatives of a function at a given point.

1. To access the numerical integration and differentiation,
3. Highlight the RUN icon and press [ENTER/EXE]
4. Press [OPTN][F4:CALC]. Then
• Press [F2:d/dx] for first derivative
• Press [F3:d^2/dx^2 for second derivative,
• or [F4:integral]

Nov 01, 2010 | Casio FX-9750GPlus Calculator

### How to calculate a finite integral

Press 2ND MATH to bring up the Math menu. Select "Calculus" and then "integrate." Enter the expression, the variable of integration, the lower limit, and the upper limit, separated by commas. Close the final paren and press ENTER or diamond ENTER.

For example, to calculate the integral from 0 to pi of sin(x) dx, you want

INT(sin(x),x,0,pi)

where INT is the integral sign and pi is the lower-case Greek pi.

Sep 22, 2010 | Texas Instruments TI-89 Calculator

### I am having trouble figuring out why my ti 89 has trouble figuring out integrals. for example i know that the integral of x^2 is x^3/3+c but my ti 89 gives me the answer in a decimal of fraction form. i do...

The calculator does not give a result of an integration with a constant. The form of the result will depend ob the EXACT/APPROXIMATE mode you have selected.
In the following screen capture, your integral has been evaluated with mode set to EXACT,AUTO, and APPROXIMATE. Pay attention to the syntax.

To set the computational mode to EXACT, press the MODE button use the Function keys F1,F2 or F3 to move from page to page, point to EXACT/APPROX and use the right arrow key to unfold the submenu, then the Up or Down arrow to select AUTO, EXACT or APPROXIMATE and press ENTER to SAVE Configuration.
If the integral cannot be found in EXACT mode, the calculator will echo the command without calculating the integral.

Apr 26, 2010 | Texas Instruments TI-89 Calculator

### Can i calculate calculus using fx-991ms

If you want to get an answer like 1/2X for d/dx(X^2), you will have to purchase a CAS calculator like Casio's Algebra FX-2 or Classpad. TI series calculators also have CAS.
However, you can calculate the numerical values of derivatives and integrals only.
To calculate the value of a proper integral:

1. Press the 'ON' key;
2. Press the Integral key ;
3. Enter your expression (example X^2+X-3 etc);
4. Press the 'comma' key after your expression;
5. Input the first limit after comma, input comma again after first limit;
6. Close brackets;
7. Press the equals key, display may return after a while with the answer.
for eg to calculate xdx from 0 to 2, input as follows:

dx(X,0,2)

To calculate derivative at a point:

1. Press Shift and then the integration key.
3. Input comma;
4. input the point at which you want to evaluate the derivative;
5. Close bracket and press enter.
Example, to calculate d/dx X^2 at 3 input:

SHIFT+dx key X^2,3)

Display looks like this: d/dx(X^2,3).

Oct 23, 2009 | Casio FX-300MS Calculator

Hello,
Clear all variables [F6] [ENTER]
Here is a screen capture of the display for your integral.

Hope it helps

Dec 27, 2008 | Texas Instruments TI-89 Calculator

### Integration with limits & with out limits

Hello,
This calculator can only perform NUMERICAL DEFINITE integrals. Which meansyou have to supply the numerical value of the lower limit and the numerical value of the upper limit. The result is a numerical value.
The calculator cannot perform symbolic calculus.

If the function is simple you find the integral in tables of integrals where you will see that INT(log(X)dx=x(log(x)+1). Some calculators that have a CAS (computer algebra system) can manipulate symbolic expression, but not theCasio FX-991ES.

You ask it the value of the integral of log(X) from X=1 to X=3 and it will give you 0.5627748004

Hope it helps

Dec 12, 2008 | Texas Instruments TI-84 Plus Calculator

### Integration, too few arguments

I reset my calculator and this solved the problem. To reset your calculator press [2nd], then [6] (Mem), press F1 (reset), Select 3 for all memory, and select Yes.

Oct 23, 2008 | Texas Instruments TI-89 Calculator

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