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AS/A-Level Mathematics - Definite integrals

Definite integrals

August 11, 2021

Integration can be used to find areas, volumes, central points and many useful things. Let's learn about definite integrals in A-Level Maths.

Definite Integral

A Definite Integral has start and end values: in other words there is an interval [a, b]. 

a and b  (called limits, bounds or boundaries) are put at the bottom and top of the "S", like this:

There are 3 stages to find the Definite Integral by calculating the Indefinite Integral at a, and at b…

1. The statement. Basically the function written out, with values for a and b 

2. After integration. The function is integrated and put into square brackets 

3. The evaluation. Round brackets are used to split the integration in two. One part for b and one for a. 

Example Question 

Evaluate the above ⬆️

Integrate the function and put it in square brackets. Put the ‘limits’ outside thebracket. 

Example Question 

The Indefinite Integral is: ∫cos(x) dx = sin(x) + C

Example Question 

Drafted by Eunice (Maths)

Reference

https://www.mathsisfun.com/calculus/integration-definite.html