How to find the eigenvalues of a matrix on a TI-89 Titanium

By E-Code · updated 2026-09-27

Type eigVl( (2nd ALPHA locks letters), the square matrix with 2nd , for [ and 2nd ÷ for ], close with ) and press ENTER: eigVl([[4,1][2,3]]) gives {5. 2.}.

Step by step

1. Type eigVl(. 2nd ALPHA ÷ 9 7 0 4 ALPHA ( Press 2nd ALPHA to lock letters, type e i g v l (÷ 9 7 0 4), then ALPHA to unlock and (. Case doesn't matter.
2. Type the matrix. 2nd , 2nd , 4 , 1 2nd ÷ 2nd , 2 , 3 2nd ÷ 2nd ÷ ) Type [[4,1][2,3]] and ). 2nd , is [ and 2nd ÷ is ]; each [ ] is one row.
3. Find the eigenvalues. ENTER Press ENTER.
4. Read the list. {5. 2.}: the eigenvalues are 5 and 2. They add up to 4+3 and multiply to the determinant, 4·3-1·2 = 10.

What the screen shows

{5. 2.}: the eigenvalues are 5 and 2. They add up to 4+3 and multiply to the determinant, 4·3-1·2 = 10.

Look for {5. 2.} on the screen.

Try it with the keys lit up

This guide is one of E-Code's Learn lessons. Open it on E-Code's TI-89 calculator and each key lights up in turn as you press it.

Try “Find the eigenvalues of a matrix” on the TI-89 calculator

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