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HOW TO ENTER A PIECEWISE-DEFINED FUNCTION ON TI83 CALCULATOR

Example:
Steps Key Sequence Screens
1. Start Equation Editor Press Y= key
2. Input First Part of Function in Parentheses  
3. Input Condition for First Part of Function in Parentheses Type left parenthesis, then X key
  Press 2nd, then MATH (for Test)
  Select appropriate test by pressing the number next to the test
  Input endpoint and right parenthesis
NOTE: For compound inequalities, 1 ≤ x ≤ 3, you will need to type the condition in two parts exactly as follows: (1 ≤ x and x ≤ 3). The function 'and' is found in the catalog (2nd then 0).
4. Add the Parts Together Press + key
5. Input Next Part Follow steps #2 and 3
6. Change Style of Graph Press MODE key
  Use arrow keys to move cursor to Dot, Press ENTER
7. Graph Press GRAPH key