Skip to main content
Ch. 8 - Techniques of Integration
Hass - Thomas' Calculus 15th Edition
Hass15th EditionThomas' CalculusISBN: 9780137616077Non è quello che usi tu?Cambia libro di testo
Capitolo 8, Problema 8.3.44

Evaluate the integrals in Exercises 33–52.
∫ sec⁶(x) dx

Guida verificata passo dopo passo
1
Recognize that the integral involves a high even power of secant: \(\int \sec^{6}(x) \, dx\). To simplify, express \(\sec^{6}(x)\) as \(\sec^{4}(x) \cdot \sec^{2}(x)\).
Rewrite \(\sec^{4}(x)\) as \((\sec^{2}(x))^{2}\), so the integral becomes \(\int (\sec^{2}(x))^{2} \cdot \sec^{2}(x) \, dx = \int \sec^{4}(x) \cdot \sec^{2}(x) \, dx\).
Use the identity \(\sec^{2}(x) = 1 + \tan^{2}(x)\) to express powers of secant in terms of tangent, or alternatively, use the reduction formula for powers of secant: \(\int \sec^{n}(x) \, dx = \frac{\sec^{n-2}(x) \tan(x)}{n-1} + \frac{n-2}{n-1} \int \sec^{n-2}(x) \, dx\) for \(n > 1\).
Apply the reduction formula with \(n=6\) to reduce the integral \(\int \sec^{6}(x) \, dx\) to an expression involving \(\int \sec^{4}(x) \, dx\).
Repeat the reduction process on \(\int \sec^{4}(x) \, dx\) until you reach integrals of \(\sec^{2}(x)\), which is straightforward to integrate, and then combine all parts to express the original integral.

Risposta video verificata per un problema simile:

Questa soluzione video è stata consigliata dai nostri tutor come utile per risolvere questo problema.
Durata del video:
2m

Concetti chiave

Ecco i concetti essenziali che devi comprendere per rispondere correttamente alla domanda.

Integration of Powers of Secant

Integrating powers of secant functions often requires using reduction formulas or expressing secant in terms of tangent and secant to simplify the integral. For even powers, it is common to separate one sec²(x) factor and use trigonometric identities to reduce the power step-by-step.
Video consigliato:
05:42
Example 6: Integral of Secant & Cosecant

Trigonometric Identities

Key identities such as sec²(x) = 1 + tan²(x) help transform the integral into a more manageable form. These identities allow substitution and reduction of powers, making it easier to integrate complex trigonometric expressions.
Video consigliato:
7:17
Verifying Trig Equations as Identities

Substitution Method

Substitution is often used when the integral contains a function and its derivative, such as tan(x) and sec²(x). By substituting u = tan(x), the integral can be rewritten in terms of u, simplifying the integration process.
Video consigliato:
07:33
Euler's Method