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HOW TO EVALUATE FUNCTIONS WITH TI89 CALCULATOR

Steps Key Sequence Screens
1. Input Function, Piecewise-Defined Function, or Parametric Equation. Press DIAMOND key, then F1 key (for Y=)
  Type the function
2. Graph Press DIAMOND key, then F3 key
3. Evaluate Function Press F5
  Press 1 (for Value)
  Type in value for x or trace function until you reach the value for x.
Note: For a parametric equation: type in value for t or trace curve until you reach the value for t.
Note: In this case, we are evaluating the function at x = –1.
  Press ENTER
Note: In this case, f(–1) = 2.