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 8.5.42

Evaluate the integrals in Exercises 39–54.
∫ sin(θ) dθ / (cos²θ + cos θ - 2)

Guida verificata passo dopo passo
1
Start by examining the integral: \(\int \frac{\sin(\theta)}{\cos^{2}(\theta) + \cos(\theta) - 2} \, d\theta\). Notice that the denominator is a quadratic expression in terms of \(\cos(\theta)\).
Let \(u = \cos(\theta)\). Then, compute \(du = -\sin(\theta) \, d\theta\), which implies \(-du = \sin(\theta) \, d\theta\). This substitution will help simplify the integral.
Rewrite the integral in terms of \(u\): replace \(\sin(\theta) \, d\theta\) with \(-du\), and the denominator becomes \(u^{2} + u - 2\). So the integral becomes \(\int \frac{-du}{u^{2} + u - 2}\).
Factor the quadratic in the denominator: \(u^{2} + u - 2 = (u + 2)(u - 1)\). This allows you to use partial fraction decomposition to express \(\frac{1}{(u + 2)(u - 1)}\) as a sum of simpler fractions.
Set up the partial fractions: \(\frac{1}{(u + 2)(u - 1)} = \frac{A}{u + 2} + \frac{B}{u - 1}\). Solve for constants \(A\) and \(B\), then integrate each term separately with respect to \(u\).

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:
3m

Concetti chiave

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

Integration of Trigonometric Functions

This involves techniques to integrate functions containing sine, cosine, and other trigonometric expressions. Recognizing patterns and using identities can simplify the integral, making it easier to solve.
Video consigliato:
Percorso guidato
6:04
Introduction to Trigonometric Functions

Trigonometric Identities and Factorization

Using identities like factoring quadratic expressions in terms of cosine helps simplify the denominator. For example, factoring cos²θ + cosθ - 2 into (cosθ + 2)(cosθ - 1) can make the integral more manageable.
Video consigliato:
7:17
Verifying Trig Equations as Identities

Substitution Method in Integration

Substitution involves changing variables to simplify the integral. Here, letting u = cosθ transforms the integral into a rational function in u, which is easier to integrate.
Video consigliato:
07:33
Euler's Method