Before you start: HOME, MODE and a clean slate
Everything below runs on the HOME screen. Press HOME, then check two settings in MODE: Angle should be RADIAN for calculus, and Exact/Approx should be AUTO, so exact input stays exact and decimal input gives a decimal. If you are unsure what the layers 2nd, ◆ and alpha do, read the keypad guide first.
Old variables are the most common reason for strange answers. If you stored 3 in x yesterday, every x today is a 3. Clear them with Clean Up: press 2nd F1 to open the F6 menu and choose NewProb.
Derivatives with d(
The derivative command sits on the 8 key as a 2nd function. The syntax is d(expression, variable), and an optional third argument gives the order, so d(f, x, 2) is the second derivative. Command page: d(.
| Input | Result |
|---|---|
| d(x^3,x) | 3·x2 |
| d(x·sin(x),x) | x·cos(x)+sin(x) |
| impDif(x^2+y^2=1,x,y) | −x/y |
| nDeriv(x^3,x)|x=2 | 12.0 |
The product rule result above comes back already simplified. For implicit differentiation, impDif( takes the equation, the independent and the dependent variable and returns dy/dx; type it from CATALOG. To get the slope at a point, add the with operator | after the expression: d(x^3,x)|x=2. The numeric command nDeriv( does the same with a decimal, as the last row shows.
On the handheld, the tangent line comes from the graph screen (F5 Math, Tangent). Calc89 also accepts tangentLine( on the home line:
| Input | Result |
|---|---|
| tangentLine(x^2,x,1) | 2·x−1 |
Integrals with ∫(, indefinite and definite
The integral sign is 2nd 7. With two arguments, ∫(expression, variable) returns an antiderivative without the constant. Add lower and upper bounds for a definite integral: ∫(expression, variable, a, b). Command page: ∫(.
| Input | Result |
|---|---|
| ∫(x,x) | x2/2 |
| ∫(x·e^x,x) | (x−1)·ex |
| nInt(x^2,x,0,1) | 0.333333333333 |
| arcLen(x^(3/2),x,0,4) | 80·√10/27−8/27 |
Integration by parts, as in the second row, needs no setup. A definite integral stays exact as long as the integrand and the bounds are exact; press ◆ ENTER when the question asks for a decimal. For a purely numeric value use nInt(. Arc length, a BC topic, has its own command arcLen( with the same four arguments as a definite integral.
Limits with limit(
limit( is item 3 in the F3 Calc menu. The syntax is limit(expression, variable, point). A fourth argument makes it one sided: a negative number approaches from the left, a positive number from the right. For limits at infinity, ∞ is ◆ CATALOG. Command page: limit(.
| Input | Result |
|---|---|
| limit(sin(x)/x,x,0) | 1 |
Solving equations, zeros and extrema
F2 opens the Algebra menu. Item 1 is solve(, which takes an equation and the variable. zeros( (item 4) takes an expression and returns a list, and nSolve( (item 8) returns one decimal root. For optimization problems, fMin( and fMax( in F3 Calc return the x value of the minimum or maximum.
| Input | Result |
|---|---|
| solve(x^2=9,x) | x=−3 or x=3 |
| solve(x^2-2=0,x) | x=−√2 or x=√2 |
| zeros(x^2-9,x) | {−3,3} |
| nSolve(x^2=2,x) | 1.41421356237 |
| fMin(x^2-4x,x) | x=2 |
| fMax(-x^2+2x,x) | x=1 |
Exact or decimal: ◆ ENTER and approx(
The TI-89 Titanium keeps π, roots and fractions exact. When a free response asks for three decimal places, press ◆ ENTER instead of ENTER, or wrap the expression in approx( (F2, item 5). The reverse works too: exact( turns a decimal into a fraction.
| Input | Result |
|---|---|
| approx(π) | 3.14159265359 |
| exact(.25) | 1/4 |
Evaluate at a point: the with operator |
The | key, left of 7, means “with”. Anything after it is substituted before the expression is evaluated, so you never have to store a value in x. For a function you reuse across several parts of a question, define it once with Define (F4, item 1) and then call it like f(3).
| Input | Result |
|---|---|
| when(x>0,1,-1)|x=2 | 1 |
| Define f(x)=x^2+1 | Done |
| f(3) | 10 |
BC topics: Taylor polynomials and series
taylor( is in the F3 Calc menu. Give the expression, the variable and the order; a fourth argument sets the center, which is 0 when you leave it out. For sums use Σ(, item 4 in F3: Σ(expression, index, start, end). The end can be ∞ for an infinite series.
| Input | Result |
|---|---|
| taylor(ℯ^(x),x,4) | x4/24+x3/6+x2/2+x+1 |
| Σ(k,k,1,10) | 55 |
On exam day
As of October 2026, the AP Calculus AB and BC exams permit the physical TI-89 Titanium on the calculator sections. Phone apps are not permitted on any standardized exam, so Calc89 stays at home. The SAT (since August 2025) and the ACT prohibit CAS calculators, including the TI-89 Titanium; see the College Board calculator policy. Use Calc89 for homework and practice: the keys are the same, so every sequence above becomes muscle memory before test day. The AI keystroke tutor in Calc89 can also show the key sequence for a problem from your worksheet.
FAQ
Is the TI-89 Titanium allowed on the AP Calculus exam?
Yes. As of October 2026, the AP Calculus AB and BC exams permit the physical TI-89 Titanium handheld on the calculator sections. Phone and tablet apps, Calc89 included, are not permitted on the exam.
Can I use the TI-89 Titanium on the SAT or ACT?
No. The SAT (since August 2025) and the ACT prohibit calculators with CAS functionality, and that includes every TI-89 model. Phone and tablet apps are not permitted on either test.
Do I need to switch to radians for AP Calculus?
Yes. Calculus results for trig functions assume radians, so set Angle to RADIAN in MODE before you start.
How do I get a decimal instead of an exact answer?
Press ◆ then ENTER instead of ENTER alone. You can also wrap the expression in approx( from the F2 Algebra menu.
Calc89 is an independent app intended for use with TI-89 Titanium. It is not affiliated with or endorsed by Texas Instruments. TI-89 Titanium is a trademark of Texas Instruments.