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### Course: AP®︎/College Calculus BC>Unit 9

Lesson 9: Calculator-active practice

# Evaluating definite integral with calculator

This video shows how to find the overlapping area between two circles using definite integrals and a graphing calculator. It demonstrates entering the integral function, specifying the variable, and setting the bounds of integration. The result matches the hand-calculated answer.

## Want to join the conversation?

• At what times can we actually use a calculator to evaluate integrals? They're (mostly) not allowed on tests...
• On the calculator section of the AP calc tests
• Can TI-84's do this? If so, I'd love the assistance!
• You can do this by pressing the 'math' button and scrolling down to fnint( ) (which is the 9th one down and will also come up by pressing '9'). This is the same function Sal uses on his 85 and once you select it the steps for inputting the function and other information are the same as in the video.
• At , Sal says that evaluating definite integrals with a calculator can be useful when you "can't actually evaluate them analytically". Are there integrals that are impossible to evaluate analytically? If so, can I see some examples?
(1 vote)
• ∫e^(x^2) dx cannot be expressed as an elementary function.
• Is it possible to cube root a number on khans' calculators?
• 8^(1/3)
• Does this method work regardless of whether you are in Function or Polar? I use a TI-84+.
• When we try to find the limits of integration, why do we have to set r equal to zero.
Can someone explain this to me.
• You set r = 0 when you cannot figure out the limits of integration just by inspection (just by looking at the graph). Usually that happens when at both bounds r = 0.
• why did you not multiply by 9/2 instead of just 9?