Trigonometric Integral Calculator

Solve trigonometric integrals symbolically. This calculator supports sine, cosine, tangent, cotangent, secant and cosecant, common trigonometric identities, powers, linear arguments, substitution patterns, Fresnel integrals, derivative verification and numerical graphing.

Calculate a Trigonometric Integral

Examples can be entered with or without explicit multiplication: 3x, 3*x, sin(3x), 2sin(x).

Common Trigonometric Integral Formulas

Integral Antiderivative
\(\int\sin x\,dx\) \(-\cos x+C\)
\(\int\cos x\,dx\) \(\sin x+C\)
\(\int\tan x\,dx\) \(-\ln|\cos x|+C\)
\(\int\cot x\,dx\) \(\ln|\sin x|+C\)
\(\int\sec x\,dx\) \(\ln|\sec x+\tan x|+C\)
\(\int\csc x\,dx\) \(-\ln|\csc x+\cot x|+C\)
\(\int\sec^2x\,dx\) \(\tan x+C\)
\(\int\csc^2x\,dx\) \(-\cot x+C\)
\(\int\sec x\tan x\,dx\) \(\sec x+C\)
\(\int\csc x\cot x\,dx\) \(-\csc x+C\)

Trigonometric Identities Used in Integration

Several difficult-looking trigonometric integrals become much simpler after applying an identity.

These identities are especially useful when integrating powers of sine, cosine, tangent and cotangent.

How to Integrate Trigonometric Functions

1. Recognize the basic derivative

Start by checking whether the integrand is directly related to a standard derivative. For example:

\[ \frac{d}{dx}\sin x=\cos x \] and \[ \frac{d}{dx}\tan x=\sec^2x. \]

2. Check for a linear argument

For an expression such as \[ \cos(5x), \] the inner derivative is \(5\), so \[ \int\cos(5x)\,dx = \frac{1}{5}\sin(5x)+C. \]

3. Look for a substitution pattern

For example, \[ \int x\cos(x^2)\,dx \] suggests \[ u=x^2,\qquad du=2x\,dx. \] Therefore, \[ \int x\cos(x^2)\,dx = \frac12\sin(x^2)+C. \]

4. Use identities for powers

For \[ \int\sin^2x\,dx, \] the power-reduction identity gives \[ \sin^2x=\frac{1-\cos(2x)}2. \]

Exact Symbolic Integration vs Numerical Integration

A symbolic antiderivative is an exact mathematical expression such as \[ -\cos x+C. \]

Numerical integration instead approximates an integral using numerical values. The graph on this page uses numerical cumulative integration only for visualization.

For definite numerical calculations, see the Definite Integral Calculator and Numerical Integration Calculator.

Domains and Discontinuities

Trigonometric functions can have discontinuities. For example, \(\tan x\), \(\sec x\), \(\cot x\) and \(\csc x\) are undefined at specific values of \(x\).

For example:

\[ \tan x=\frac{\sin x}{\cos x} \] so tangent is undefined whenever \[ \cos x=0. \]

The graph therefore breaks the numerical curve when it encounters undefined or extremely large values instead of drawing a misleading line through an asymptote.

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Frequently Asked Questions

What is a trigonometric integral?

A trigonometric integral is an integral containing one or more trigonometric functions, including sine, cosine, tangent, cotangent, secant and cosecant.

What is the integral of sin(x)?

\[ \int\sin(x)\,dx=-\cos(x)+C. \]

What is the integral of cos(x)?

\[ \int\cos(x)\,dx=\sin(x)+C. \]

What is the integral of sec²(x)?

\[ \int\sec^2(x)\,dx=\tan(x)+C. \]

How do I integrate sin²(x)?

Use the power-reduction identity \[ \sin^2x=\frac{1-\cos(2x)}2. \] This converts the squared sine into a constant and a cosine term that can be integrated directly.

What is the integral of tan²(x)?

Use \[ \tan^2x=\sec^2x-1. \] Therefore, \[ \int\tan^2x\,dx=\tan x-x+C. \]

Why does the calculator use Fresnel functions?

Integrals such as \[ \int\sin(x^2)\,dx \] and \[ \int\cos(x^2)\,dx \] do not have elementary antiderivatives. Fresnel functions provide standard exact special-function representations.

What does the constant C mean?

The constant \(C\) represents an arbitrary constant. All functions that differ only by a constant have the same derivative.

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