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How to work out a definite integral on a TI-84 Plus CE

By E-Code · updated

Press MATH and 9 for the ∫ template, type the lower limit, ▶, the upper limit, ▶, the function, ▶ and the variable, then ▶ and ENTER. With 0, 2, X² and X it gives 2.666…, which is 8/3.

Step by step

  1. Open MATH. MATH Press MATH. Item 9, further down the list, is fnInt(, the definite integral.
  2. Pick fnInt(. 9 Press 9. The ∫ template appears, with the cursor in the lower limit box at the bottom.
  3. The lower limit. 0 ▶ Type 0, then press ▶ to move to the upper limit box.
  4. The upper limit. 2 ▶ Type 2, then press ▶ to move into the brackets.
  5. The function. X,T,θ,n X² ▶ Type X,T,θ,n then x² for X², then press ▶ to the box after the d.
  6. The variable. X,T,θ,n ▶ Type X,T,θ,n for dX: X is the variable. Press ▶ to leave the template.
  7. Work it out. ENTER Press ENTER.
  8. Read the integral. 2.666…, which is 8/3: the integral of X² from 0 to 2. MATH 1 (►Frac) would show it as 8/3.

What the screen shows

2.666…, which is 8/3: the integral of X² from 0 to 2. MATH 1 (►Frac) would show it as 8/3.

Look for 2.666666667 on the screen.

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