07 3-3 (a) The definite integral and the fundamental theorem of calculus
Meaning
- The indefinite integral contains an arbitrary constant, so it does not give a definite number.
- The difference between its values at and does not depend on the constant:
- This number is the definite integral.
Fundamental theorem of calculus
- If is continuous on and is any antiderivative of on :
- and are the lower and upper limits of the integral.
- The value is a real number that depends only on , and ; the name of the variable does not matter: .
- You may drop the constant when evaluating, because it cancels in .
- Every rule of indefinite integration and every standard integral still applies.
- A continuous function on is integrable on .
| Point of comparison | Indefinite integral | Definite integral |
|---|---|---|
| Result | A family of functions | One real number |
| Constant | Present | Not needed |
| Limits | None | Lower and upper |
✍️ Worked examples
Example 14: Find .
Solution:
- is a continuous polynomial.
- .
- .
- .