B. Trigonometric FunctionsThe TI-89 has keys for sine, cosine, and tangent. You can use a ratio to graph cosecant, secant, and cotangent. Or, you can create user-defined functions.

1. Entering Sine, Cosine, and Tangent Functions

To access the trigonometric keys, use the key strokes shown below.

Function Enter Keys sine cosine tangentWhen you access one of these functions, the TI-89 will also enter the left parenthesis. Notice that in the functions below, you have to be careful when entering a trigonometric function raised to a power. is entered using .

Functions Calculator Entry2. Entering Cosecant, Secant, and Cotangent Functions

You can enter these functions using the reciprocal identities, or you can create user-defined functions. For some functions, there can be more than one way to enter it. As you gain experience, you will learn alternate ways that you may prefer.

Functions Calculator Entry