Whether you are dealing with fractions, factoring polynomials, reducing algebraic expressions, solving equations, or finding derivatives and integrals, the TI-89 Programmable Graphing Calculator automatically gives you the right answer, so you can immediately find out if your answer is right or wrong, even for the even-numbered exercises in your textbook.
The TI-89 has a wide variety of graphing capabilities, too.

Because the TI-89 calculator is programmable, if you want to practice with a special kind of complex problems, all you have to do is find a program that solves the particular type of problem you are practicing with. Then you can enter that program into the TI-89, and use it to verify your results. It's almost like having a teacher right next to you giving you the right answer to each problem.

In this page you will find the following:

A) Product links

B) Questions and Answers

C) Example Programs

D) Links to other TI-89 related sites

Please email me (tutor@sdmath.com) with any questions about how to solve mathematical problems using the TI-89 Titanium graphing calculator.

Question #1

"In the equation 2^x+3^x=13 obviously x=2
but how can I let my ti-89 titanium show how it have been solved?"

Answer:

• The instruction solve() can take not only one, but two or more equations as input.
• In general, the instruction returns solution candidates, not necessarily actual solutions.
• The manual talks about different "goals" for different settings of the Exact/Aprox mode.
• Sometimes, iterative searches are employed.
• The solution interval can be restricted using the "|" operator.
• Somehow, the results returned by solve() are always considered as Boolean ones.
• In some cases, the instruction returns infinite sets of solutions, represented by the symbol @n placed to the left of an integer between 1 and 255.

To get an aproximate solution for an equation of the form 2^x + 3^x = n, where n is a positive number, you can start by getting lower and upper bounds for the solution set.
To this end you can separately solve the equations 3^x = n (for the lower bound) as well as 2^x = n (for the upper bound) by taking the base 3 and base 2 logarithms of n, respectively.
Then you run an iterative binary search by splitting the interval at midpoint and comparing the result of the function there with those given by the end points.
Of course the TI-89 will give you the result directly and probably much faster.

Question #2

"What I am interested in is being able to add, subtract, multiply and divide, feet, inches and fractions of inches, along with the accounting, statistical and financial applications that are built into these graphing calculators.
I haven’t seen any information on the TI83 or TI84 that shows these features even exist on the TI83 or TI84.
Would the TI-89 family or Voyage 200 calculator be a better choice for my requirements and can you give me some examples of how these features work in the TI89?
I'll try to give an example:
I would like to be able to edit and recall this view and previous views as necessary:

1000' 4 1/8" + 1' 0 3/8" + 2500' 2 1/2" - 11 11/16" + 2' 4" + 16" = 3505' 2 11/16"
(automatically simplify as necessary)"

Answer:

A)
The TI-89 adds, subtracts, multiplies and divides fractions. It automatically simplifies the result and it can present it either as a fraction or as a decimal.

B)
However, I see no apparent way to input mixed number format into the calculations. For example, when trying to input the sum
(1 unit and 1/2) plus (3 units and 3/4),
the sequence of keystrokes
1 [space] 1/2 [space] + [space] 3 [space] 3/4 [enter]
is interpreted by the TI-89 as if meaning
1*(1/2) + 3*(3/4)
and it gives
11/4
as a final answer, instead of any expression representing the expected mixed number
5 units and 1/4
Now, if we enter the calculation in the following form
1+1/2+3+3/4 [enter]
then we get the correct answer
21/4
but still, this fraction is not in a mixed number format.

C)
The TI-89 has a [units] key, which opens a Units menu.
This menu includes a wide variety of standard physical units for length, time, volume, weight, etc.
From this menu we can select meters, yards, feet or inches to enter after each one of the numbers we are including in the calculation.
But the result is given in terms of only one standard unit, not two. For example
1000_ft + (4+1/8)_in + 1_ft + (3/8)_in [enter]
gives the following result
1001.38_ft
where the end result is given in feet and expressed as a decimal, not as a fraction.

D)
If the Unit System (option from the Mode menu, accessible through the [mode] key) happens to be set to SI (Standard International) instead of the English/US option, then the result from the same calculation above will show as
305.219_m
because the 1001.38 feet are automatically converted to meters.

E)
Here is my suggestion on how to manually work out your feet-inch-fraction-of-inch calculations.
You could input them in the following way:

• Enter the feet values as regular integers.
• Enter the inch values enclosed by parenthesis appending a “divided by 12” notation after closing the parenthesis.
• Inside the parenthesis, separate each whole inch value from the fraction-of-inch value with a “+” sign.

F)
With regards to being able to edit and store those calculations, the history area of the TI-89 calculator Home screen displays up to eight entry/answer pairs. These pairs scroll off the top of the screen as new calculations are performed.
If you want to permanently store your calculations and their results, you can move the cursor into the history area, highlight your entries and answers, copy them and then paste them into a session of the Text Editor application. They will stay there unchanged until you edit them or erase the corresponding text editor variable from memory.

G)
The program shown below as Example Program #8 automaticaly performs the necessary calculations.
For each term of the sum, it takes three values as input: feet, inches and fraction-of-inch values.
It can take as many number of terms as necessary.
The result is simplified and expressed also in terms of feet, inches and fraction-of-inch values.

Please email me (tutor@sdmath.com) with any request you may have for mathematical programs to run in the TI-89 Titanium calculator.

Example Program #1
Distance between two points (x1,y1) and (x2,y2) in the coordinate plane.

:dst(a,b,c,d)
:√((a-c)^2+(b-d)^2)

Example Program #2
Coordinates for the midpoint between points (x1,y1) and (x2,y2) in the coordinate plane.

:mdpt(a,b,c,d)
:Prgm
:ClrIO
:string((a+c)/2)→m
:string((b+d)/2)→n
:"("&m&" , "&n&")"→o
:Disp "Midpoint coordinates are:",o
:Pause "Press Enter to continue"
:DispHome
:EndPrgm

Example Program #3
Slope of the line that passes through the points (x1,y1) and (x2,y2) in the coordinate plane.

:slp(a,b,c,d)
:Prgm
:ClrIO
:If a=c Then
:Disp "Line is vertical or"
:Disp "it is just a point."
:Disp "The slope is undefined"
:Else
: (d-b)/(c-a)→s
: Disp "The slope is:",s
:EndIf
:Pause "Press Enter to continue"
:DispHome
:EndPrgm

Example Program #4
Equation of the line that passes through the points (x1,y1) and (x2,y2) in the coordinate plane.

:lineq(a,b,c,d)
:Prgm
:ClrIO
:string(d-b)→p
:string(a-c)→q
:string(c*b-a*d)→r
:p&"x+"&q&"y+"&r&"=0"→s
:Disp "Line equation is:",s
:Pause "Press Enter to continue"
:DispHome
:EndPrgm

Example Program #5
Equation of the mediatrix of the segment given by the points (x1,y1) and (x2,y2) in the coordinate plane.
This is the line perpendicular to the segment and passing through its midpoint.

:mdtx(a,b,c,d)
:Prgm
:ClrIO
:string(a-c)→p
:string(b-d)→q
:string((c^2+d^2-a^2-b^2)/2)→r
:p&"x+"&q&"y+"&r&"=0"→s
:Disp "Mediatrix equation is:",s
:Pause "Press Enter to continue"
:DispHome
:EndPrgm

Example Program #6
Equation of the circle with center at (a,b) and passing through the point (c,d) in the coordinate plane.

:cpcrc(a,b,c,d)
:Prgm
:ClrIO
:string(a)→k
:string(b)→l
:string(c)→m
:string(d)→n
:string(-2*a)→p
:string(-2*b)→q
:string(2*(a*c+b*d)-c^2-d^2)→r
:"x^2 + y^2 +"&p&"x+"&q&"y+"&r&"=0"→s
:Disp "Equation of the circle"
:Disp "with center ("&k&","&l&") and"
:Disp "passing through ("&m&","&n&")"
:Disp "is:",s
:Pause "Press Enter to continue"
:DispHome
:EndPrgm

Example Program #7
Equation of the circle with diameter given by endpoints (a,b) and (c,d) in the coordinate plane.

:dmcrc(a,b,c,d)
:Prgm
:ClrIO
:string(a)→k
:string(b)→l
:string(c)→m
:string(d)→n
:string(-a-c)→p
:string(-b-d)→q
:string(a*c+b*d)→r
:"x^2 + y^2 +"&p&"x+"&q&"y+"&r&"=0"→s
:Disp "Equation of the circle"
:Disp "with diameter given by"
:Disp "points ("&k&","&l&") and ("&m&","&n&")"
:Disp "is:",s
:Pause "Press Enter to continue"
:DispHome
:EndPrgm

Example Program #8
For adding up any given number of terms with feet, inches and fractions of an inch each, and getting the final sum in the same format.

:smfi()
:Prgm
:ClrIO
:setMode("Pretty Print","On")
:0→i
:0→f
:0→n
:Lbl nwtrm
:n+1→n
:""→a
:""→b
:""→c
:Dialog
:Title "Term number "&string(n)
:Request "Number of feet",a
:Request "Whole inches",b
:Request "Fraction of inch",c
:EndDlog
:If ok=1 Then
:expr(a)→d
:expr(b)→e
:expr(c)→q
:d+f→f
:q+e+i→i
:EndIf
:Dialog
:Title "Another term?"
:Text "OK to enter more values"
:Text "ESC to finish the sum"
:EndDlog
:If ok=1
:Goto nwtrm
:int(i/12)→g
:f+g→h
:i-g*12→k
:Disp "Total feet = "&string(h)
:Disp "Whole inches = "&string(int(k))
:Disp "Fraction inch = "&string(k-int(k))
:Pause "Press Enter to continue"
:DispHome
:EndPrgm

Ray Kremer - TI-Graphing Calculator FAQ

Giulio Barozzi - Elementary number theory with the TI-89/92R

Texas Instruments - Homework Help - Math & Science

ti89.com - Comprehensive Math software for TI89/Titanium/Voyage200

ticalc.org - TI calculators programming resources