Mathematics and Statistics · Class 12 Commerce
Ch 6Definite Integration — Class 12 Mathematics and Statistics, concept-first.
In the previous chapter, integration reversed differentiation: given a function , its indefinite integral was itself a function (an antiderivative, plus an arbitrary constant ).
Key concepts
Hover a concept to preview it and jump to its most relevant Q&A.
Definite Integral and the Fundamental Theorem
The definite integral evaluates to a number. By the Fundamental Theorem of Calculus, if then ; the arbitrary constant cancels on subtraction. The result is the net signed area between and the -axis over .
Most relevant Q&A
- Evaluate $\displaystyle\int_{2}^{4} (x + 3)\,dx$.Free
- Evaluate $\displaystyle\int_{1}^{3} (2x + 1)\,dx$.Free
- Evaluate the following definite integral: $\int_1^3 \log x\, dx$Preview
- $\int_0^2 e^x \, dx$ = ______. (a) $e^2 - 1$ (b) $1 - e^2$ (c) $e - 1$ (d) $1 - e$Preview
- Evaluate: $\int_1^2 \frac{1}{x^2 + 6x + 5} \, dx$Preview
Chapter contents
The NCERT structure, section by section. Open a section to see its questions, then read the concept-first solution.
The Definite Integral and the Fundamental Theorem
In the previous chapter, integration reversed differentiation: given a function , its indefinite integral was itself a function (an antiderivative, plus an arbitrary constant ).
Standard Definite Integrals and Linearity
Evaluating a definite integral needs the same list of standard antiderivatives used for indefinite integration, now applied between limits.
Properties of Definite Integrals
Definite integrals obey several properties that often make evaluation far shorter than direct antidifferentiation. Each is stated below with the situation it is used in.
Evaluation by Substitution
When the integrand is a composite function times (a constant multiple of) the derivative of the inner function, the substitution method simplifies it.
Even and Odd Functions over Symmetric Limits
When the limits of integration are symmetric about — that is, of the form to — the symmetry of the integrand can be exploited to shorten or immediately settle the integral.
Exercises
+−Show 5 questionsHide questions5 questions
- Q10Evaluate $\displaystyle\int_{2}^{4} (x + 3)\,dx$.Free
- Q11Evaluate $\displaystyle\int_{1}^{2} (x^{2} + 2x)\,dx$.Free
- Q12Evaluate $\displaystyle\int_{1}^{3} \frac{1}{x}\,dx$.Preview
- Q13Evaluate $\displaystyle\int_{0}^{1} 3x^{2}\,e^{x^{3}}\,dx$ using substitution.Preview
- Q14Evaluate $\displaystyle\int_{0}^{1} \frac{x}{x^{2} + 1}\,dx$ using substitution.Preview
Sample & Board Papers
Sample papers and previous-year board questions for this subject.
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- Q1$\int_{-5}^{5} \dfrac{x^7}{x^4 + 10}\, dx =$ ______. (a) 10 (b) 5 (c) 0 (d) $\dfrac{1}{5}$Preview
- Q2Evaluate the following definite integral: $\int_1^3 \log x\, dx$Preview
- Q3$\int_0^2 e^x \, dx$ = ______. (a) $e^2 - 1$ (b) $1 - e^2$ (c) $e - 1$ (d) $1 - e$Preview
- Q4Evaluate: $\int_1^3 \frac{\sqrt{x + 5}}{\sqrt{x + 5} + \sqrt{9 - x}} \, dx$Preview
- Q5$\displaystyle\int_a^b f(x)\, dx = \int_a^b f(t)\, dt$ (a) True (b) FalsePreview
- Q6$\int_2^7 \frac{\sqrt{x}}{\sqrt{x} + \sqrt{9 - x}} \, dx$ = ______. (a) $\frac{7}{2}$ (b) $\frac{5}{2}$ (c) 7 (d) 2Preview
- Q7Evaluate: $\int_1^2 \frac{1}{x^2 + 6x + 5} \, dx$Preview
- Q8If $\int_0^a 3x^2\,dx = 8$ then $a$ = ______. (a) 2 (b) 0 (c) $\frac{8}{3}$ (d) 1Preview
- Q9Evaluate the following integrals: $\int_2^7 \frac{\sqrt{x}}{\sqrt{x} + \sqrt{9 - x}}\,dx$Preview
- Q10Evaluate: $\displaystyle\int_0^2 \dfrac{1}{\sqrt{4 - x^2}}\, dx$Preview
- Q11Evaluate: $\displaystyle\int_3^9 \dfrac{\sqrt[3]{12 - x}}{\sqrt[3]{x} + \sqrt[3]{12 - x}}\, dx$Preview
More questions
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- Example 1Evaluate $\displaystyle\int_{1}^{3} (2x + 1)\,dx$.Free
- Example 2Evaluate $\displaystyle\int_{0}^{2} (3x^{2} - 2x + 1)\,dx$.Free
- Example 3Evaluate $\displaystyle\int_{1}^{2} \frac{1}{x}\,dx$.Free
- Example 4Evaluate $\displaystyle\int_{0}^{1} e^{x}\,dx$.Preview
- Example 5If $\displaystyle\int_{0}^{2} f(x)\,dx = 5$ and $\displaystyle\int_{2}^{6} f(x)\,dx = 3$, find (i) $\displaystyle\int_{0}^{6} f(x)\,dx$ and…Preview
- Example 6Evaluate $\displaystyle\int_{0}^{1} 2x\,(x^{2}+1)^{3}\,dx$ using substitution.Preview
- Example 7Evaluate $\displaystyle\int_{1}^{e} \frac{\log x}{x}\,dx$ using substitution.Preview
- Example 8Evaluate $\displaystyle I = \int_{0}^{4} \frac{\sqrt{x}}{\sqrt{x} + \sqrt{4 - x}}\,dx$ using a property of definite integrals.Preview
- Example 9Evaluate $\displaystyle\int_{-1}^{1} (x^{2} + 1)\,dx$ using the even/odd function property, and state the value of $\displaystyle\int_{-2}^{…Preview