How Do Definite Integrals Differ from Indefinite Integrals?
FAQs on Difference Between Indefinite and Definite Integrals
1. What is the difference between an integral and a definite integral?
The main difference between an integral and a definite integral is that a definite integral calculates a specific numerical value over a given interval, while an indefinite integral represents a general antiderivative with a constant of integration.
Key points:
- Indefinite integral gives a family of functions (F(x) + C).
- Definite integral evaluates the exact area under a curve between two limits [a, b].
- Definite integral has upper and lower limits; indefinite does not.
2. What is an indefinite integral?
An indefinite integral represents the antiderivative of a function without specific limits.
- It is written as ∫f(x) dx = F(x) + C, where C is the constant of integration.
- It defines all possible functions whose derivative is f(x).
- No numerical value is calculated in an indefinite integral.
3. What is a definite integral?
A definite integral finds the net area under a curve between two specific values.
- It is represented as ∫ba f(x) dx, where 'a' is the lower limit and 'b' is the upper limit.
- The result is a numerical value, not a function.
- It is used to compute areas, displacement, and other quantities with fixed boundaries.
4. How are indefinite and definite integrals represented symbolically?
Indefinite and definite integrals use similar symbols but differ in limits.
- Indefinite integral: ∫f(x) dx (no limits)
- Definite integral: ∫ba f(x) dx (with upper and lower limits 'b' and 'a')
5. What are some applications of definite integrals?
Definite integrals are commonly used to find areas, volumes, and accumulated values.
- Calculate area under a curve between two points.
- Find total distance, work done, or volume of solids of revolution.
- Used in physics, engineering, and economics for quantities with fixed limits.
6. What is the main similarity between indefinite and definite integrals?
Both indefinite and definite integrals involve finding antiderivatives of a function.
- They use the same integration rules and formulas.
- Both help in reversing differentiation.
- Integration is the fundamental process in each case; the difference is in the presence or absence of limits.
7. How do you evaluate a definite integral?
To evaluate a definite integral, find the antiderivative and subtract its value at the lower limit from its value at the upper limit.
- Find F(x), the antiderivative of f(x).
- Apply limits: F(b) - F(a).
- The answer is a specific numerical value.
8. Why is a constant of integration not included in definite integrals?
A constant of integration is not shown in definite integrals because it cancels out during evaluation.
- When calculating F(b) - F(a), the constant C is subtracted from itself.
- This ensures the result is only based on the values at the limits.
9. Can indefinite and definite integrals be used to solve real-world problems?
Yes, both indefinite and definite integrals solve various real-life and mathematical problems.
- Indefinite integrals help find general solutions to differential equations.
- Definite integrals are used for precise calculations like area, volume, and accumulated change.
10. Give an example to illustrate the difference between indefinite and definite integrals.
An example shows the distinction between indefinite and definite integrals.
- Indefinite: ∫x2 dx = (1/3)x3 + C
- Definite: ∫20 x2 dx = [ (1/3)x3 ]20 = (8/3) - 0 = 8/3
So, the indefinite integral gives a function, while the definite integral gives a value.






















