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Integral formulas

The integral formulas you use most, from basic antiderivatives to substitution, integration by parts, trig and rational functions, and properties of definite integrals. Each section links to practice problems.

Basic antiderivatives

Below, CC is the constant of integration and log⁡\log is the natural logarithm (ln⁡\ln).

FunctionIndefinite integralNote
xnx^nxn+1n+1+C\dfrac{x^{n+1}}{n+1} + Cn=0,1,2,…n = 0, 1, 2, \ldots
xαx^\alphaxα+1α+1+C\dfrac{x^{\alpha+1}}{\alpha+1} + Cα≠−1\alpha \ne -1 (real)
1x\dfrac{1}{x}log⁡∣x∣+C\log|x| + CKeep the absolute value
exe^xex+Ce^x + C
axa^xaxlog⁡a+C\dfrac{a^x}{\log a} + Ca>0, a≠1a > 0,\ a \ne 1
sin⁡x\sin x−cos⁡x+C-\cos x + C
cos⁡x\cos xsin⁡x+C\sin x + C
1cos⁡2x\dfrac{1}{\cos^2 x}tan⁡x+C\tan x + C
1sin⁡2x\dfrac{1}{\sin^2 x}−1tan⁡x+C-\dfrac{1}{\tan x} + C
tan⁡x\tan x−log⁡∣cos⁡x∣+C-\log|\cos x| + CBy substitution
log⁡x\log xxlog⁡x−x+Cx\log x - x + CBy parts

→ Practice: indefinite integrals of polynomials

→ Practice: basic indefinite integrals

Linearity and linear inner functions

Linearity
∫kf(x) dx=k∫f(x) dx,∫{f(x)±g(x)} dx=∫f(x) dx±∫g(x) dx\int kf(x)\,dx = k\int f(x)\,dx,\qquad \int \{f(x) \pm g(x)\}\,dx = \int f(x)\,dx \pm \int g(x)\,dx
Linear inside

If F(x)F(x) is an antiderivative of f(x)f(x) (a≠0a \ne 0),

∫f(ax+b) dx=1aF(ax+b)+C\int f(ax+b)\,dx = \frac{1}{a}F(ax+b) + C
FunctionIndefinite integral
(ax+b)n(ax+b)^n(ax+b)n+1a(n+1)+C\dfrac{(ax+b)^{n+1}}{a(n+1)} + Cn≠−1n \ne -1
1ax+b\dfrac{1}{ax+b}1alog⁡∣ax+b∣+C\dfrac{1}{a}\log|ax+b| + C
eax+be^{ax+b}1aeax+b+C\dfrac{1}{a}e^{ax+b} + C
sin⁡(ax+b)\sin(ax+b)−1acos⁡(ax+b)+C-\dfrac{1}{a}\cos(ax+b) + C
cos⁡(ax+b)\cos(ax+b)1asin⁡(ax+b)+C\dfrac{1}{a}\sin(ax+b) + C

Substitution and integration by parts

Substitution
∫f(g(x))g′(x) dx=∫f(t) dt(t=g(x))\int f(g(x))g'(x)\,dx = \int f(t)\,dt \quad (t = g(x))
∫f′(x)f(x) dx=log⁡∣f(x)∣+C\int \frac{f'(x)}{f(x)}\,dx = \log|f(x)| + C
Integration by parts
∫f(x)g′(x) dx=f(x)g(x)−∫f′(x)g(x) dx\int f(x)g'(x)\,dx = f(x)g(x) - \int f'(x)g(x)\,dx
FunctionIndefinite integral
xexxe^x(x−1)ex+C(x-1)e^x + C
x2exx^2e^x(x2−2x+2)ex+C(x^2-2x+2)e^x + CBy parts twice
xsin⁡xx\sin x−xcos⁡x+sin⁡x+C-x\cos x + \sin x + C
xcos⁡xx\cos xxsin⁡x+cos⁡x+Cx\sin x + \cos x + C
xlog⁡xx\log xx22log⁡x−x24+C\dfrac{x^2}{2}\log x - \dfrac{x^2}{4} + C
eaxsin⁡bxe^{ax}\sin bxeax(asin⁡bx−bcos⁡bx)a2+b2+C\dfrac{e^{ax}(a\sin bx - b\cos bx)}{a^2+b^2} + CCyclic
eaxcos⁡bxe^{ax}\cos bxeax(acos⁡bx+bsin⁡bx)a2+b2+C\dfrac{e^{ax}(a\cos bx + b\sin bx)}{a^2+b^2} + CCyclic

→ Practice: integration by substitution

→ Practice: integration by parts

Trigonometric integrals and identities

Double- and half-angle identities
sin⁡2x=2sin⁡xcos⁡x,sin⁡2x=1−cos⁡2x2,cos⁡2x=1+cos⁡2x2\sin 2x = 2\sin x\cos x,\qquad \sin^2 x = \frac{1-\cos 2x}{2},\qquad \cos^2 x = \frac{1+\cos 2x}{2}
Triple-angle identities (lowering powers)
sin⁡3x=3sin⁡x−sin⁡3x4,cos⁡3x=3cos⁡x+cos⁡3x4\sin^3 x = \frac{3\sin x - \sin 3x}{4},\qquad \cos^3 x = \frac{3\cos x + \cos 3x}{4}
Product-to-sum formulas
sin⁡αcos⁡β=12{sin⁡(α+β)+sin⁡(α−β)}\sin\alpha\cos\beta = \frac{1}{2}\{\sin(\alpha+\beta)+\sin(\alpha-\beta)\}
cos⁡αcos⁡β=12{cos⁡(α+β)+cos⁡(α−β)}\cos\alpha\cos\beta = \frac{1}{2}\{\cos(\alpha+\beta)+\cos(\alpha-\beta)\}
sin⁡αsin⁡β=−12{cos⁡(α+β)−cos⁡(α−β)}\sin\alpha\sin\beta = -\frac{1}{2}\{\cos(\alpha+\beta)-\cos(\alpha-\beta)\}
FunctionIndefinite integral
sin⁡2x\sin^2 xx2−sin⁡2x4+C\dfrac{x}{2} - \dfrac{\sin 2x}{4} + C
cos⁡2x\cos^2 xx2+sin⁡2x4+C\dfrac{x}{2} + \dfrac{\sin 2x}{4} + C
tan⁡2x\tan^2 xtan⁡x−x+C\tan x - x + C
sin⁡3x\sin^3 x−cos⁡x+13cos⁡3x+C-\cos x + \dfrac{1}{3}\cos^3 x + C
1cos⁡x\dfrac{1}{\cos x}12log⁡1+sin⁡x1−sin⁡x+C\dfrac{1}{2}\log\dfrac{1+\sin x}{1-\sin x} + C

→ Practice: trigonometric integrals

Rational and irrational functions

FunctionIndefinite integralNote
1(x+a)(x+b)\dfrac{1}{(x+a)(x+b)}1b−alog⁡∣x+ax+b∣+C\dfrac{1}{b-a}\log\left|\dfrac{x+a}{x+b}\right| + Ca≠ba \ne b
1x2−a2\dfrac{1}{x^2-a^2}12alog⁡∣x−ax+a∣+C\dfrac{1}{2a}\log\left|\dfrac{x-a}{x+a}\right| + Ca>0a > 0
1x2+a2\dfrac{1}{x^2+a^2}1aarctan⁡xa+C\dfrac{1}{a}\arctan\dfrac{x}{a} + CUniversity
1a2−x2\dfrac{1}{\sqrt{a^2-x^2}}arcsin⁡xa+C\arcsin\dfrac{x}{a} + CUniversity
1x2+A\dfrac{1}{\sqrt{x^2+A}}log⁡∣x+x2+A∣+C\log\left|x+\sqrt{x^2+A}\right| + CUniversity
a2−x2\sqrt{a^2-x^2}12(xa2−x2+a2arcsin⁡xa)+C\dfrac{1}{2}\left(x\sqrt{a^2-x^2}+a^2\arcsin\dfrac{x}{a}\right) + CUniversity
ax+b\sqrt{ax+b}23a(ax+b)ax+b+C\dfrac{2}{3a}(ax+b)\sqrt{ax+b} + C

→ Practice: rational functions (partial fractions)

→ Practice: integrals with inverse trig functions

Definite integrals

Basics
∫abf(x) dx=[F(x)]ab=F(b)−F(a)\int_a^b f(x)\,dx = \Bigl[F(x)\Bigr]_a^b = F(b) - F(a)
∫abf(x) dx+∫bcf(x) dx=∫acf(x) dx,∫baf(x) dx=−∫abf(x) dx\int_a^b f(x)\,dx + \int_b^c f(x)\,dx = \int_a^c f(x)\,dx,\qquad \int_b^a f(x)\,dx = -\int_a^b f(x)\,dx
Even and odd functions
∫−aa(even) dx=2∫0a(even) dx,∫−aa(odd) dx=0\int_{-a}^{a}(\text{even})\,dx = 2\int_0^a(\text{even})\,dx,\qquad \int_{-a}^{a}(\text{odd})\,dx = 0
The 1/6 formula
∫αβ(x−α)(x−β) dx=−16(β−α)3\int_\alpha^\beta (x-\alpha)(x-\beta)\,dx = -\frac{1}{6}(\beta-\alpha)^3
Fundamental theorem of calculus
ddx∫axf(t) dt=f(x)\frac{d}{dx}\int_a^x f(t)\,dt = f(x)
Wallis formula
∫0π2sin⁡nx dx=∫0π2cos⁡nx dx={n−1n⋅n−3n−2⋯12⋅π2(n even)n−1n⋅n−3n−2⋯23(n odd)\int_0^{\frac{\pi}{2}}\sin^n x\,dx = \int_0^{\frac{\pi}{2}}\cos^n x\,dx = \begin{cases}\dfrac{n-1}{n}\cdot\dfrac{n-3}{n-2}\cdots\dfrac{1}{2}\cdot\dfrac{\pi}{2} & (n\ \text{even})\\[1.5ex]\dfrac{n-1}{n}\cdot\dfrac{n-3}{n-2}\cdots\dfrac{2}{3} & (n\ \text{odd})\end{cases}

→ Practice: definite integrals of polynomials

→ Practice: definite integrals (advanced)

Area and volume

Area

If f(x)≥g(x)f(x) \ge g(x) on a≤x≤ba \le x \le b, the area between the curves is

S=∫ab{f(x)−g(x)} dxS = \int_a^b \{f(x) - g(x)\}\,dx
Parabola and line

If the difference is a(x−α)(x−β)a(x-\alpha)(x-\beta),

S=∣a∣6(β−α)3S = \frac{|a|}{6}(\beta-\alpha)^3
Volume of revolution

Rotating the region under y=f(x)y = f(x) between x=ax = a and x=bx = b about the xx-axis gives a solid of volume

V=π∫ab{f(x)}2 dxV = \pi\int_a^b \{f(x)\}^2\,dx

→ Practice: area between curves (with figures)

Improper and double integrals

IntegralValueCondition
∫1∞dxxp\displaystyle\int_1^\infty \frac{dx}{x^p}1p−1\dfrac{1}{p-1}Converges for p>1p > 1
∫01dxxp\displaystyle\int_0^1 \frac{dx}{x^p}11−p\dfrac{1}{1-p}Converges for p<1p < 1
∫0∞xne−x dx\displaystyle\int_0^\infty x^n e^{-x}\,dxn!n!Gamma function
∫−∞∞e−x2 dx\displaystyle\int_{-\infty}^{\infty} e^{-x^2}\,dxπ\sqrt{\pi}Gaussian integral
∫0∞e−axsin⁡bx dx\displaystyle\int_0^\infty e^{-ax}\sin bx\,dxba2+b2\dfrac{b}{a^2+b^2}a>0a > 0
Polar coordinates
x=rcos⁡θ,y=rsin⁡θ⟹dx dy=r dr dθx = r\cos\theta,\quad y = r\sin\theta \quad\Longrightarrow\quad dx\,dy = r\,dr\,d\theta

→ Practice: improper integrals

→ Practice: double integrals