Table of integrals
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Integration is one of the two basic operations in calculus and since it, unlike differentiation, is non-trivial, tables of known integrals are often useful. This page lists some of the most common antiderivatives; a more complete list can be found in the List of integrals.
We use C for an arbitrary constant of integration that can only be determined if something about the value of the integral at some point is known. Thus each function has an infinite number of antiderivatives.
These formulas only state in another form the assertions in the table of derivatives.
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Rules for integration of general functions
- <math>\int af(x)\,dx = a\int f(x)\,dx</math>
- <math>\int [f(x) + g(x)]\,dx = \int f(x)\,dx + \int g(x)\,dx</math>
- <math>\int f(x)g(x)\,dx = f(x)\int g(x)\,dx - \int \left(d[f(x)]\int g(x)\,dx\right)\,dx</math>
Integrals of simple functions
Rational functions
- more integrals: List of integrals of rational functions
- <math>\int \,dx = x + C</math>
- <math>\int x^n\,dx = \frac{x^{n+1}}{n+1} + C\qquad\mbox{ if }n \ne -1</math>
- <math>\int \frac{1}{x}\,dx = \ln{\left|x\right|} + C</math>
- <math>\int {dx \over {a^2+x^2}} = {1 \over a}\arctan {x \over a} + C</math>
Irrational functions
- more integrals: List of integrals of irrational functions
- <math>\int {dx \over \sqrt{a^2-x^2}} = \arcsin {x \over a} + C</math>
- <math>\int {-dx \over \sqrt{a^2-x^2}} = \arccos {x \over a} + C</math>
- <math>\int {dx \over x\sqrt{x^2-a^2}} = {1 \over a}\mbox{arcsec}\,{|x| \over a} + C</math>
Logarithms
- more integrals: List of integrals of logarithmic functions
- <math>\int \ln {x}\,dx = x \ln {x} - x + C</math>
- <math>\int \log_b {x}\,dx = x\log_b {x} - x\log_b {e} + C</math>
Exponential functions
- more integrals: List of integrals of exponential functions
- <math>\int e^x\,dx = e^x + C</math>
- <math>\int a^x\,dx = \frac{a^x}{\ln{a}} + C</math>
Trigonometric functions
- more integrals: List of integrals of trigonometric functions and List of integrals of arc functions
- <math>\int \sin{x}\, dx = -\cos{x} + C</math>
- <math>\int \cos{x}\, dx = \sin{x} + C</math>
- <math>\int \tan{x} \, dx = -\ln{\left| \cos {x} \right|} + C</math>
- <math>\int \cot{x} \, dx = \ln{\left| \sin{x} \right|} + C</math>
- <math>\int \sec{x} \, dx = \ln{\left| \sec{x} + \tan{x}\right|} + C</math>
- <math>\int \csc{x} \, dx = -\ln{\left| \csc{x} + \cot{x}\right|} + C</math>
- <math>\int \sec^2 x \, dx = \tan x + C</math>
- <math>\int \csc^2 x \, dx = -\cot x + C</math>
- <math>\int \sec{x} \, \tan{x} \, dx = \sec{x} + C</math>
- <math>\int \csc{x} \, \cot{x} \, dx = - \csc{x} + C</math>
- <math>\int \sin^2 x \, dx = \frac{1}{2}(x - \sin x \cos x) + C</math>
- <math>\int \cos^2 x \, dx = \frac{1}{2}(x + \sin x \cos x) + C</math>
- <math>\int \sin^n x \, dx = - \frac{\sin^{n-1} {x} \cos {x}}{n} + \frac{n-1}{n} \int \sin^{n-2}{x} \, dx</math>
- <math>\int \cos^n x \, dx = - \frac{\cos^{n-1} {x} \sin {x}}{n} + \frac{n-1}{n} \int \cos^{n-2}{x} \, dx</math>
- <math>\int \arctan{x} \, dx = x \, \arctan{x} - \frac{1}{2} \ln{\left| 1 + x^2\right|} + C</math>
Hyperbolic functions
- more integrals: List of integrals of hyperbolic functions
- <math>\int \sinh x \, dx = \cosh x + C</math>
- <math>\int \cosh x \, dx = \sinh x + C</math>
- <math>\int \tanh x \, dx = \ln |\cosh x| + C</math>
- <math>\int \mbox{csch}\,x \, dx = \ln\left| \tanh {x \over2}\right| + C</math>
- <math>\int \mbox{sech}\,x \, dx = \arctan(\sinh x) + C</math>
- <math>\int \coth x \, dx = \ln|\sinh x| + C</math>
Definite integrals
There are some functions whose antiderivatives cannot be expressed in closed form. However, the values of the definite integrals of some of these functions over some common intervals can be calculated. A few useful definite integrals are given below.
- <math>\int_0^\infty{\sqrt{x}\,e^{-x}\,dx} = \frac{1}{2}\sqrt \pi</math> (see also Gamma function)
- <math>\int_0^\infty{e^{-x^2}\,dx} = \frac{1}{2}\sqrt \pi</math> (the Gaussian integral)
- <math>\int_0^\infty{\frac{x}{e^x-1}\,dx} = \frac{\pi^2}{6}</math> (see also Bernoulli number)
- <math>\int_0^\infty{\frac{x^3}{e^x-1}\,dx} = \frac{\pi^4}{15}</math>
- <math>\int_0^\infty\frac{\sin(x)}{x}\,dx=\frac{\pi}{2}</math>
- <math>\int_0^\infty x^{z-1}\,e^{-x}\,dx = \Gamma(z)</math> (where <math>\Gamma(z)</math> is the Gamma function.)
- <math>\int_{-\infty}^\infty e^{-(ax^2+bx+c)}\,dx=\sqrt{\frac{\pi}{a}}e^\frac{b^2-4ac}{4a}</math>ar:جدول التكاملات
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