Skip to main content
Ch. 5 - Trigonometric Identities
Lial - Trigonometry 12th Edition
Lial12th EditionTrigonometryISBN: 9780136552161, 9780135440780, 9780136881117, 9780135440827, 9780135924891Non è quello che usi tu?Cambia libro di testo
Capitolo 6, Problema 18

Perform each indicated operation and simplify the result so that there are no quotients.
(tan x + cot x)²

Guida verificata passo dopo passo
1
Start by writing the expression explicitly: \( (\tan x + \cot x)^2 \).
Recall that \( \tan x = \frac{\sin x}{\cos x} \) and \( \cot x = \frac{\cos x}{\sin x} \). Substitute these into the expression: \( \left( \frac{\sin x}{\cos x} + \frac{\cos x}{\sin x} \right)^2 \).
Find a common denominator for the terms inside the parentheses, which is \( \sin x \cos x \), and rewrite the sum as a single fraction: \( \left( \frac{\sin^2 x + \cos^2 x}{\sin x \cos x} \right)^2 \).
Use the Pythagorean identity \( \sin^2 x + \cos^2 x = 1 \) to simplify the numerator, so the expression becomes \( \left( \frac{1}{\sin x \cos x} \right)^2 \).
Square the fraction to get \( \frac{1}{\sin^2 x \cos^2 x} \). To eliminate quotients, rewrite this as \( \csc^2 x \sec^2 x \), since \( \csc x = \frac{1}{\sin x} \) and \( \sec x = \frac{1}{\cos x} \).

Risposta video verificata per un problema simile:

Questa soluzione video è stata consigliata dai nostri tutor come utile per risolvere questo problema.

Concetti chiave

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

Trigonometric Identities

Trigonometric identities are equations involving trigonometric functions that hold true for all values within their domains. They allow simplification and transformation of expressions, such as converting quotients into products or sums, which is essential for simplifying (tan x + cot x)².
Video consigliato:
Percorso guidato
5:32
Fundamental Trigonometric Identities

Pythagorean Identity

The Pythagorean identity states that sin²x + cos²x = 1. This fundamental relation helps express tangent and cotangent in terms of sine and cosine, enabling the simplification of expressions involving tan x and cot x by rewriting them without quotients.
Video consigliato:
Percorso guidato
6:25
Pythagorean Identities

Algebraic Expansion and Simplification

Expanding expressions like (tan x + cot x)² involves applying the distributive property (a + b)² = a² + 2ab + b². After expansion, combining like terms and using trigonometric identities helps eliminate quotients and simplify the expression to a more manageable form.
Video consigliato:
Percorso guidato
04:12
Algebraic Operations on Vectors