Skip to content
K Knidox Search…
Reference · Formulas

Integral Table

Common indefinite integrals and integration rules — filter and copy.

Click any formula to copy it.

A definite integral is the shaded area under the curve
Curve y = x squared from x = 0 to x = 3 with the region between the curve and the x-axis shaded, representing the definite integral as the area under the curve90x = 0x = 3

An integral table lists antiderivatives of common functions. For example ∫ xⁿ dx = xⁿ⁺¹/(n + 1) + C when n ≠ −1, ∫ eˣ dx = eˣ + C, and ∫ sin x dx = −cos x + C. Every indefinite integral carries a “+ C”, the arbitrary constant of integration.

How to read this table

Integration is the reverse of differentiation: an antiderivative of a function f is any function whose derivative is f. Because the derivative of a constant is zero, every function has infinitely many antiderivatives differing by a constant, so each indefinite integral ends in “+ C”. To check any line, differentiate the right-hand side — you should recover the integrand. For instance, the derivative of −cos x is sin x, which confirms ∫ sin x dx = −cos x + C.

Families of integrals

The basic forms cover powers, reciprocals, exponentials, and logarithms. The trigonometric forms invert the derivatives of the six trig functions. The inverse-trig forms recognise rational and radical expressions whose antiderivatives are arctan or arcsin. The rules — constant multiple, sum, and integration by parts — let you break a complicated integral into these standard pieces.

Basic integrals

Powers, reciprocals, exponentials, and logarithms. Here k and a are constants.

IntegralNotes
∫ k dx = kx + CConstant times x
∫ xⁿ dx = xⁿ⁺¹/(n + 1) + CPower rule, valid for n ≠ −1
∫ (1/x) dx = ln|x| + CThe n = −1 case
∫ eˣ dx = eˣ + Ceˣ is its own antiderivative
∫ aˣ dx = aˣ/ln a + CFor a > 0, a ≠ 1
∫ ln x dx = x ln x − x + CFound via integration by parts

Trigonometric integrals

The antiderivatives of the six trig functions and their standard combinations.

IntegralNotes
∫ sin x dx = −cos x + Cd/dx(−cos x) = sin x
∫ cos x dx = sin x + Cd/dx(sin x) = cos x
∫ sec²x dx = tan x + Cd/dx(tan x) = sec²x
∫ csc²x dx = −cot x + Cd/dx(−cot x) = csc²x
∫ sec x tan x dx = sec x + Cd/dx(sec x) = sec x tan x
∫ csc x cot x dx = −csc x + Cd/dx(−csc x) = csc x cot x
∫ tan x dx = −ln|cos x| + CEquivalently ln|sec x| + C
∫ cot x dx = ln|sin x| + Cd/dx(ln|sin x|) = cot x
∫ sec x dx = ln|sec x + tan x| + CStandard secant integral
∫ csc x dx = −ln|csc x + cot x| + CStandard cosecant integral

Inverse-trig forms and rules

Antiderivatives that produce inverse trig functions, plus the linearity and parts rules.

IntegralNotes
∫ 1/(1 + x²) dx = arctan x + Cd/dx(arctan x) = 1/(1 + x²)
∫ 1/√(1 − x²) dx = arcsin x + CValid for −1 < x < 1
∫ c·f(x) dx = c ∫ f(x) dxConstant multiple rule
∫ [f(x) ± g(x)] dx = ∫ f(x) dx ± ∫ g(x) dxSum and difference rule
∫ u dv = uv − ∫ v duIntegration by parts

Why “+ C” is not optional

Leaving off the constant of integration is the most common mistake with indefinite integrals. Because any two antiderivatives of the same function differ only by a constant, the answer is a whole family of functions, not one — writing “+ C” records that. The constant only disappears in a definite integral, where the two constants cancel when you subtract the bounds. Whenever you are unsure of a result, differentiate it: integration and differentiation are inverse operations, so a correct antiderivative must give back the original integrand.

Why do I add “+ C” to every indefinite integral?
Because the derivative of a constant is zero, a function has infinitely many antiderivatives that differ only by a constant. The “+ C” records that whole family; without it you have named just one of many valid answers.
What is the power rule for integrals, and why n ≠ −1?
The power rule is ∫ xⁿ dx = xⁿ⁺¹/(n + 1) + C. It fails at n = −1 because that would divide by n + 1 = 0. The n = −1 case is handled separately: ∫ (1/x) dx = ln|x| + C.
How do I check an integral is correct?
Differentiate your answer. Integration reverses differentiation, so a correct antiderivative must give back the integrand — for example d/dx(−cos x) = sin x confirms ∫ sin x dx = −cos x + C.
When do I use integration by parts?
Use ∫ u dv = uv − ∫ v du when the integrand is a product whose factors integrate or differentiate more simply, such as x·eˣ or ln x. Choose u so that du is simpler and dv so that v is easy to find.
What is the difference between an indefinite and a definite integral?
An indefinite integral returns a family of antiderivatives with a “+ C”. A definite integral evaluates that antiderivative at two limits and subtracts, giving a number; the constants cancel, so no “+ C” appears.
Why is ∫ (1/x) dx equal to ln|x| and not just ln x?
The absolute value extends the result to negative x, where ln x is undefined. For x < 0 the derivative of ln|x| is still 1/x, so ln|x| + C is the antiderivative on both sides of zero.