E-CodePrecalc & Trig on a TI-89: how-to guides
4 guides for precalc & trig on the TI-89 Titanium. Each one shows the keys to press, step by step.
The guides
- Get exact trig values: 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.
- Expand and collect trig identities: Press F2 9 (Trig) and 1 for tExpand(: tExpand(cos(x-y)) gives cos(x)·cos(y)+sin(x)·sin(y).
- Switch to degree mode: Press MODE, ▼ three times to Angle, ▶ to open the choices, 2 for DEGREE and ENTER to save.
- Convert a complex number to polar form: Type the complex number (2nd CATALOG is ί), press 2nd MODE for ▶, type Polar and press ENTER: in degree mode (3.+4.ί)▶Polar gives (5.∠53.1301), length 5 at 53.13°.