How to get exact trig values on a TI-89 Titanium

By E-Code · updated 2026-09-27

In radian mode, press 2nd Y for sin(, 2nd ^ for π, finish the angle and press ENTER: sin(π/3) gives the exact √(3)/2.

Step by step

1. Type sin(. 2nd Y Press 2nd, then Y. SIN is written above Y, so this types sin(.
2. Type π. 2nd ^ Press 2nd, then ^. π is written above the ^ key.
3. Finish the angle. ÷ 3 ) Press ÷, 3 and ) to make π/3, which is 60° in radians.
4. Get the exact value. ENTER Press ENTER. The TI-89 is in radian mode unless you change it.
5. Read the answer. sin(π/3) = √(3)/2, the exact value from the unit circle. ◆ ENTER would give .866025.

What the screen shows

sin(π/3) = √(3)/2, the exact value from the unit circle. ◆ ENTER would give .866025.

Look for √(3)/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 “Get exact trig values” on the TI-89 calculator

Related

• Expand and collect trig identities
• Switch to degree mode
• Convert a complex number to polar form

Math programs for the TI-89 Titanium:

• Quadratic roots, exact when possible
• Linear system, exact answers
• Fraction calculator: exact, mixed, decimal

All TI-89 precalc & trig guides · All TI-89 guides · All calculator guides