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## HOW TO FIND THE ROOT OF A FUNCTION WITH TI89 CALCULATOR

 Steps Key Sequence Screens 1. Input Function or Piecewise-Defined Function. Press DIAMOND key, then F1 key (for Y=) Type the function Method 1: Using home screen. 2. Go to Home screen Press 2nd, then ESC 3. Select zeros function Press F2 Press 4 (for zeros() 4. Type in Function Note: You can either type in the function directly (e.g., 5 – 2x2 + x3) OR, if you followed step 1 above, use y1(x) 4. Type in Independent Variable Press comma key, then x, then right parenthesis Note: This will find ALL zeros of the function on the whole domain of the function. 5. Solve ENTER Note: If this returns something other than a value, then press DIAMOND key, then ENTER. Alternatively, you can use the TI89's solve function. Method 2: Using grapher. Follow Step 1 above Type the function 2. Graph Press DIAMOND key, then F3 key 3. Find in Press F5 Press 2 (for Zero) Type in x-value for a point to the left of x-intercept or trace function until you reach the value for x Press ENTER Type in x-value for a point to the right of x-intercept or trace function until you reach the value for x Press ENTER Note: In this case, the root of the function is x = –1.2419.