TI-89 Polynomial Root Finder
Use the Polynomial Root Finder app on a TI-89 or TI-89 Titanium to enter coefficients, calculate real and complex roots, and send a polynomial to the graph screen. These steps follow Texas Instruments’ official app workflow.
Written and checked by TheToolNet Editorial Team · Last reviewed: August 21, 2026 · Editorial policy
Choose the degree first, then enter coefficients from the highest power down to the constant term.
How to use Polynomial Root Finder on a TI-89
- Open the app. Press APPS, highlight the Polynomial Root Finder entry, and press ENTER.
- Start a new problem. Choose New, then select the polynomial degree.
- Enter the coefficients. Fill an, an−1, through a0. Use 0 when a power is missing.
- Solve. Select the on-screen Solve command to display the roots.
- Graph if useful. The official app can save the polynomial to the Y= Editor so it can be viewed in the calculator’s graph environment.
TI-89 worked example
Solve x³ + 5x² − 2x − 24 = 0. Select degree 3 and enter these four coefficients in order:
| Field | a₃ | a₂ | a₁ | a₀ |
|---|---|---|---|---|
| Value | 1 | 5 | −2 | −24 |
The polynomial factors as (x − 2)(x + 3)(x + 4), so the roots are 2, −3 and −4. This is also the example used in Texas Instruments’ app materials, making it a useful check that the entries are in the correct order.
Common TI-89 root-finder problems
| Problem | What to check |
|---|---|
| Wrong answers or an unexpected degree | Make sure missing powers have a zero coefficient and entries run from the highest power to the constant. |
| The app is not in the APPS list | Download only from the official TI software page, confirm model compatibility, then follow TI’s transfer instructions and license. |
| A root contains i | That is a non-real complex root, not an error. Real-coefficient polynomials produce non-real roots in conjugate pairs. |
| A graph seems to miss roots | Complex roots do not cross the real x-axis. Adjust the graph window if real crossings are outside the visible range. |
| Tiny imaginary parts appear near real roots | Numerical rounding can affect difficult or repeated roots. Substitute the displayed value back into the polynomial to judge the residual. |
TI-89 app versus the online finder
| Feature | TI-89 app | TheToolNet finder |
|---|---|---|
| Where it runs | Compatible TI graphing calculator | Modern web browser |
| Maximum degree | Up to degree 30 according to TI | Degree 10 |
| Real and complex roots | Yes | Yes |
| Graph workflow | Can send to Y= Editor | No graph; shows factors and residual check |
| Account | No account for on-device use | No account |
The online finder is convenient for checking work and viewing a substitution residual. The TI app is better suited to an approved calculator workflow or degrees above 10. Always follow the rules for calculators in your course or exam.
Frequently asked questions
Does the TI-89 Polynomial Root Finder solve complex roots?
Yes. Texas Instruments describes the app as finding real and complex roots.
Can I type the entire equation into the app?
The standard Polynomial Root Finder workflow uses coefficient fields. Select the degree, then enter each coefficient in descending order.
Does this guide provide the TI app download?
No. Use the official Texas Instruments page below so you receive the software and documentation under TI’s current license terms.
Is TheToolNet affiliated with Texas Instruments?
No. TheToolNet is an independent educational tool site. TI-89 and Texas Instruments are referenced only to explain the device workflow.
Official source and related calculator
Download information, compatibility and guidebooks are available from the official Texas Instruments Polynomial Root Finder page. To solve a polynomial in your browser, use our online polynomial root finder.