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Integrals · Antiderivatives

Integration of trigonometric functions

$\sin^2 x$, $\tan^3 x\cdot\sec^2 x$ or $\cos(4x-1)$ are not in the table of standard integrals as they stand. But with a trigonometric identity, or by spotting the hidden chain, they turn into something that is. There is no new technique here: it is just the table of standard integrals plus identities from 1st Bachillerato.

Before you start, make sure you know: Double-angle ratios (1st Bachillerato (Technology))
Before you start, make sure you know: Rules of differentiation (1st Bachillerato (Technology))

First check whether it is the chain in disguise

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Find the indefinite integral of the following function, noting that it is a composite function containing the derivative of the argument:…

Find the indefinite integral of the following function, noting that it is a composite function containing the derivative of the argument:

$\int x \cdot \sin(x^2 + 3) \, dx$

Solve

Disguised power: $\sin^n x\cdot\cos x$ and similar

Flow diagram showing the integration of tangent cubed times secant squared, identifying u as tangent and applying the composite power rule. tan³x · sec²x u=tan x, u'=sec²x tan⁴x / 4 + C rule uⁿ·u'
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Find the indefinite integral of the function $f(x) = \tan^3(x) \cdot \sec^2(x)$. Remember to check whether the expression fits a power-type integral where a function is…

Find the indefinite integral of the function $f(x) = \tan^3(x) \cdot \sec^2(x)$. Remember to check whether the expression fits a power-type integral where a function is raised to an exponent and multiplied by its derivative.

Solve

Identities to remove even powers: $\sin^2$, $\cos^2$, $\tan^2$

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On many occasions, trigonometric identities allow us to transform a difficult expression into an immediate one. Use the relation $\tan^2(x) + 1 = \sec^2(x)$ to calculate…

On many occasions, trigonometric identities allow us to transform a difficult expression into an immediate one. Use the relation $\tan^2(x) + 1 = \sec^2(x)$ to calculate the following antiderivative:

$\int \tan^2(x) \, dx$

tan²(x) + 1 = sec²(x) tan²(x) = sec²(x) - 1 ∫ tan²(x) dx = ∫ ( sec²(x) - 1) dx
Solve
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An architecture firm is designing the profile of a ramp for an extreme sports park. The gradient of the ramp at each point $x$ is given by the function…

An architecture firm is designing the profile of a ramp for an extreme sports park. The gradient of the ramp at each point $x$ is given by the function $g(x) = \sin^2(x)$. If the ramp starts at the point $(0, 0)$, determine the function $G(x)$ that describes the height of the ramp at any point.

x y G(x) Height x Gradient g(x) = sin²(x) (0,0)
Solve

Combining identity and chain in a single integral

Practice★☆☆Not started
To start practising finding antiderivatives, find the general antiderivative of the following function, which includes a linear adjustment in the argument of the cosine:…

To start practising finding antiderivatives, find the general antiderivative of the following function, which includes a linear adjustment in the argument of the cosine:

$f(x) = \cos(4x - 1)$

X Y 1 −1 1 −1 f(x) = cos(4x - 1) Δx=1/4 1/4 T = π/2 ∫
Solve
Practice★★☆Not started
Calculate the antiderivative of the following trigonometric function using fundamental identities to simplify the expression before integrating: $$f(x) =…

Calculate the antiderivative of the following trigonometric function using fundamental identities to simplify the expression before integrating:

$$f(x) = \frac{\cos^3(x)}{1 - \sin(x)}$$ x y π/2 π -π/2 -π 1 −1 f(x) = cos³(x) 1 - sin(x) Trigonometric identity: cos²(x) + sin²(x) = 1 Antiderivative ∫ f(x) dx = ?
Solve

Summary

See all the exercises in this section