Integration is the basic operation in
integral calculus
In mathematics, an integral is the continuous analog of a sum, which is used to calculate areas, volumes, and their generalizations. Integration, the process of computing an integral, is one of the two fundamental operations of calculus,Int ...
. While
differentiation has straightforward
rules
Rule or ruling may refer to:
Human activity
* The exercise of political or personal control by someone with authority or power
* Business rule, a rule pertaining to the structure or behavior internal to a business
* School rule, a rule tha ...
by which the derivative of a complicated
function can be found by differentiating its simpler component functions, integration does not, so tables of known integrals are often useful. This page lists some of the most common
antiderivative
In calculus, an antiderivative, inverse derivative, primitive function, primitive integral or indefinite integral of a continuous function is a differentiable function whose derivative is equal to the original function . This can be stated ...
s.
Historical development of integrals
A compilation of a list of integrals (Integraltafeln) and techniques of integral calculus was published by the German mathematician (also spelled Meyer Hirsch) in 1810. These tables were republished in the United Kingdom in 1823. More extensive tables were compiled in 1858 by the Dutch mathematician
David Bierens de Haan for his ''
Tables d'intégrales définies'', supplemented by ''
Supplément aux tables d'intégrales définies'' in ca. 1864. A new edition was published in 1867 under the title ''
Nouvelles tables d'intégrales définies''.
These tables, which contain mainly integrals of elementary functions, remained in use until the middle of the 20th century. They were then replaced by the much more extensive tables of
Gradshteyn and Ryzhik
''Gradshteyn and Ryzhik'' (''GR'') is the informal name of a comprehensive table of integrals originally compiled by the Russian mathematicians I. S. Gradshteyn and I. M. Ryzhik. Its full title today is ''Table of Integrals, Series, and Products ...
. In Gradshteyn and Ryzhik, integrals originating from the book by Bierens de Haan are denoted by BI.
Not all
closed-form expression
In mathematics, an expression or equation is in closed form if it is formed with constants, variables, and a set of functions considered as ''basic'' and connected by arithmetic operations (, and integer powers) and function composition. ...
s have closed-form antiderivatives; this study forms the subject of
differential Galois theory, which was initially developed by
Joseph Liouville
Joseph Liouville ( ; ; 24 March 1809 – 8 September 1882) was a French mathematician and engineer.
Life and work
He was born in Saint-Omer in France on 24 March 1809. His parents were Claude-Joseph Liouville (an army officer) and Thérès ...
in the 1830s and 1840s, leading to
Liouville's theorem which classifies which expressions have closed-form antiderivatives. A simple example of a function without a closed-form antiderivative is , whose antiderivative is (up to constants) the
error function
In mathematics, the error function (also called the Gauss error function), often denoted by , is a function \mathrm: \mathbb \to \mathbb defined as:
\operatorname z = \frac\int_0^z e^\,\mathrm dt.
The integral here is a complex Contour integrat ...
.
Since 1968 there is the
Risch algorithm for determining indefinite integrals that can be expressed in term of
elementary function
In mathematics, an elementary function is a function of a single variable (typically real or complex) that is defined as taking sums, products, roots and compositions of finitely many polynomial, rational, trigonometric, hyperbolic, a ...
s, typically using a
computer algebra system
A computer algebra system (CAS) or symbolic algebra system (SAS) is any mathematical software with the ability to manipulate mathematical expressions in a way similar to the traditional manual computations of mathematicians and scientists. The de ...
. Integrals that cannot be expressed using elementary functions can be manipulated symbolically using general functions such as the
Meijer G-function.
Lists of integrals
More detail may be found on the following pages for the lists of
integral
In mathematics, an integral is the continuous analog of a Summation, sum, which is used to calculate area, areas, volume, volumes, and their generalizations. Integration, the process of computing an integral, is one of the two fundamental oper ...
s:
*
List of integrals of rational functions
*
List of integrals of irrational functions
*
List of integrals of trigonometric functions
*
List of integrals of inverse trigonometric functions
*
List of integrals of hyperbolic functions
*
List of integrals of inverse hyperbolic functions
*
List of integrals of exponential functions
The following is a list of integrals of exponential functions. For a complete list of integral functions, please see the list of integrals.
Indefinite integral
Indefinite integrals are antiderivative functions. A constant (the constant of integ ...
*
List of integrals of logarithmic functions
*
List of integrals of Gaussian functions
Gradshteyn,
Ryzhik,
Geronimus,
Tseytlin, Jeffrey, Zwillinger, and
Moll's (GR) ''
Table of Integrals, Series, and Products'' contains a large collection of results. An even larger, multivolume table is the ''Integrals and Series'' by
Prudnikov,
Brychkov, and
Marichev (with volumes 1–3 listing integrals and series of
elementary and
special functions
Special functions are particular mathematical functions that have more or less established names and notations due to their importance in mathematical analysis, functional analysis, geometry, physics, or other applications.
The term is defined by ...
, volume 4–5 are tables of
Laplace transform
In mathematics, the Laplace transform, named after Pierre-Simon Laplace (), is an integral transform that converts a Function (mathematics), function of a Real number, real Variable (mathematics), variable (usually t, in the ''time domain'') to a f ...
s). More compact collections can be found in e.g. Brychkov, Marichev, Prudnikov's ''Tables of Indefinite Integrals'', or as chapters in Zwillinger's ''CRC Standard Mathematical Tables and Formulae'' or
Bronshtein and Semendyayev's ''
Guide Book to Mathematics'', ''
Handbook of Mathematics'' or ''
Users' Guide to Mathematics'', and other mathematical handbooks.
Other useful resources include
Abramowitz and Stegun
''Abramowitz and Stegun'' (''AS'') is the informal name of a 1964 mathematical reference work edited by Milton Abramowitz and Irene Stegun of the United States National Bureau of Standards (NBS), now the National Institute of Standards and T ...
and the
Bateman Manuscript Project. Both works contain many identities concerning specific integrals, which are organized with the most relevant topic instead of being collected into a separate table. Two volumes of the Bateman Manuscript are specific to integral transforms.
There are several web sites which have tables of integrals and integrals on demand.
Wolfram Alpha
WolframAlpha ( ) is an answer engine developed by Wolfram Research. It is offered as an online service that answers factual queries by computing answers from externally sourced data.
History
Launch preparations for WolframAlpha began on Ma ...
can show results, and for some simpler expressions, also the intermediate steps of the integration.
Wolfram Research
Wolfram Research, Inc. ( ) is an American Multinational corporation, multinational company that creates computational technology. Wolfram's flagship product is the technical computing program Wolfram Mathematica, first released on June 23, 1988. ...
also operates another online service, the Mathematica Online Integrator.
Integrals of simple functions
''C'' is used 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
antiderivative
In calculus, an antiderivative, inverse derivative, primitive function, primitive integral or indefinite integral of a continuous function is a differentiable function whose derivative is equal to the original function . This can be stated ...
s.
These formulas only state in another form the assertions in the
table of derivatives.
Integrals with a singularity
When there is a
singularity in the function being integrated such that the antiderivative becomes undefined at some point (the singularity), then ''C'' does not need to be the same on both sides of the singularity. The forms below normally assume the
Cauchy principal value around a singularity in the value of ''C'', but this is not necessary in general. For instance, in
there is a singularity at 0 and the
antiderivative
In calculus, an antiderivative, inverse derivative, primitive function, primitive integral or indefinite integral of a continuous function is a differentiable function whose derivative is equal to the original function . This can be stated ...
becomes infinite there. If the integral above were to be used to compute a definite integral between −1 and 1, one would get the wrong answer 0. This however is the Cauchy principal value of the integral around the singularity. If the integration is done in the complex plane the result depends on the path around the origin, in this case the singularity contributes −''i'' when using a path above the origin and ''i'' for a path below the origin. A function on the real line could use a completely different value of ''C'' on either side of the origin as in:
Rational functions
*
The following function has a non-integrable singularity at 0 for :
*
(
Cavalieri's quadrature formula)
*
*
**More generally,
[Reader Survey: log, ''x'', + ''C'']
, Tom Leinster, ''The ''n''-category Café'', March 19, 2012
*
Exponential functions
*
*
*
*
*
(if
is a positive integer)
*
(if
is a positive integer)
Logarithms
*
*
Trigonometric functions
*
*
*
*
*
** (See
Integral of the secant function. This result was a well-known conjecture in the 17th century.)
*
*
*
*
*
*
*
*
*
*
** (See
integral of secant cubed.)
*
*
*
Inverse trigonometric functions
*
*
*
*
*
*
Hyperbolic functions
*
*
*
*
*
*
*
*
*
*
Inverse hyperbolic functions
*
*
*
*
*
*
Products of functions proportional to their second derivatives
*
*
*
*
Absolute-value functions
Let be a
continuous function
In mathematics, a continuous function is a function such that a small variation of the argument induces a small variation of the value of the function. This implies there are no abrupt changes in value, known as '' discontinuities''. More preci ...
, that has at most one
zero
0 (zero) is a number representing an empty quantity. Adding (or subtracting) 0 to any number leaves that number unchanged; in mathematical terminology, 0 is the additive identity of the integers, rational numbers, real numbers, and compl ...
. If has a zero, let be the unique antiderivative of that is zero at the root of ; otherwise, let be any antiderivative of . Then
where is the
sign function
In mathematics, the sign function or signum function (from '' signum'', Latin for "sign") is a function that has the value , or according to whether the sign of a given real number is positive or negative, or the given number is itself zer ...
, which takes the values −1, 0, 1 when is respectively negative, zero or positive.
This can be proved by computing the derivative of the right-hand side of the formula, taking into account that the condition on is here for insuring the continuity of the integral.
This gives the following formulas (where ), which are valid over any interval where is continuous (over larger intervals, the constant must be replaced by a
piecewise constant function):
*
when is odd, and
.
*
when
for some integer .
*
when
for some integer .
*
when
for some integer .
*
when
for some integer .
If the function does not have any continuous antiderivative which takes the value zero at the zeros of (this is the case for the sine and the cosine functions), then is an antiderivative of on every
interval on which is not zero, but may be discontinuous at the points where . For having a continuous antiderivative, one has thus to add a well chosen
step function
In mathematics, a function on the real numbers is called a step function if it can be written as a finite linear combination of indicator functions of intervals. Informally speaking, a step function is a piecewise constant function having on ...
. If we also use the fact that the absolute values of sine and cosine are periodic with period , then we get:
*
*
Special functions
, :
Trigonometric integral
In mathematics, trigonometric integrals are a indexed family, family of nonelementary integrals involving trigonometric functions.
Sine integral
The different sine integral definitions are
\operatorname(x) = \int_0^x\frac\,dt
\operato ...
s, :
Exponential integral
In mathematics, the exponential integral Ei is a special function on the complex plane.
It is defined as one particular definite integral of the ratio between an exponential function and its argument.
Definitions
For real non-zero values of&nb ...
, :
Logarithmic integral function
In mathematics, the logarithmic integral function or integral logarithm li(''x'') is a special function. It is relevant in problems of physics and has number theory, number theoretic significance. In particular, according to the prime number the ...
, :
Error function
In mathematics, the error function (also called the Gauss error function), often denoted by , is a function \mathrm: \mathbb \to \mathbb defined as:
\operatorname z = \frac\int_0^z e^\,\mathrm dt.
The integral here is a complex Contour integrat ...
*
*
*
*
*
*
Definite integrals lacking closed-form antiderivatives
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 integrals are given below.
*
(see also
Gamma function
In mathematics, the gamma function (represented by Γ, capital Greek alphabet, Greek letter gamma) is the most common extension of the factorial function to complex numbers. Derived by Daniel Bernoulli, the gamma function \Gamma(z) is defined ...
)
*
for (the
Gaussian integral
The Gaussian integral, also known as the Euler–Poisson integral, is the integral of the Gaussian function f(x) = e^ over the entire real line. Named after the German mathematician Carl Friedrich Gauss, the integral is
\int_^\infty e^\,dx = \s ...
)
*
for
*
for , is a positive integer and is the
double factorial
In mathematics, the double factorial of a number , denoted by , is the product of all the positive integers up to that have the same Parity (mathematics), parity (odd or even) as . That is,
n!! = \prod_^ (n-2k) = n (n-2) (n-4) \cdots.
Restated ...
.
*
when
*
for ,
*
(see also
Bernoulli number
In mathematics, the Bernoulli numbers are a sequence of rational numbers which occur frequently in analysis. The Bernoulli numbers appear in (and can be defined by) the Taylor series expansions of the tangent and hyperbolic tangent function ...
)
*
*
*
(see
sinc function and the
Dirichlet integral)
*
*
(if is a positive integer and !! is the
double factorial
In mathematics, the double factorial of a number , denoted by , is the product of all the positive integers up to that have the same Parity (mathematics), parity (odd or even) as . That is,
n!! = \prod_^ (n-2k) = n (n-2) (n-4) \cdots.
Restated ...
).
*
(for integers with and , see also
Binomial coefficient
In mathematics, the binomial coefficients are the positive integers that occur as coefficients in the binomial theorem. Commonly, a binomial coefficient is indexed by a pair of integers and is written \tbinom. It is the coefficient of the t ...
)
*
(for real, a non-negative integer, and an odd, positive integer; since the integrand is
odd)
*
(for integers with and , see also
Binomial coefficient
In mathematics, the binomial coefficients are the positive integers that occur as coefficients in the binomial theorem. Commonly, a binomial coefficient is indexed by a pair of integers and is written \tbinom. It is the coefficient of the t ...
)
*
(for integers with and , see also
Binomial coefficient
In mathematics, the binomial coefficients are the positive integers that occur as coefficients in the binomial theorem. Commonly, a binomial coefficient is indexed by a pair of integers and is written \tbinom. It is the coefficient of the t ...
)
*