E-Code

How to work out a definite integral on the home screen on a TI-84 Plus or TI-83 Plus

By E-Code · updated

Press MATH and 9 for fnInt(, then type the function, the variable, the lower and upper limits with commas between, close the bracket and press ENTER. fnInt(X²,X,0,2) 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. fnInt( is pasted on the home screen.
  3. The function. X,T,θ,n X² , Type X,T,θ,n then x² for X², and a comma: the function to integrate.
  4. The variable. X,T,θ,n , Type X,T,θ,n and a comma: X is the variable.
  5. The limits. 0 , 2 ) Type 0 , 2 and ): integrate from X = 0 to X = 2.
  6. Work it out. ENTER Press ENTER.
  7. 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.

Try it with the keys lit up

This guide is one of E-Code's Learn lessons. Open it on E-Code's TI-84 calculator and each key lights up in turn as you press it.

Try “Work out a definite integral on the home screen” on the TI-84 calculator

Related

Math programs for the TI-84 Plus CE:

All TI-84 calculus guides · All TI-84 guides · All calculator guides