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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 5.1.39

For each expression in Column I, choose the expression from Column II that completes an identity. One or both expressions may need to be rewritten.
-tan x cos x


II
A. sin ^2 x/cos ^2 x
B.1/(sec ^2 x)
C. sin (-x)
D. csc ^2 x-cot ^2 x + sin ^2 x
E. tan x

Guida verificata passo dopo passo
1
Identify the given expression in Column I: \(-\tan x \cos x\).
Recall the definition of tangent in terms of sine and cosine: \(\tan x = \frac{\sin x}{\cos x}\).
Rewrite the expression by substituting \(\tan x\) with \(\frac{\sin x}{\cos x}\): \(-\tan x \cos x = -\left(\frac{\sin x}{\cos x}\right) \cos x\).
Simplify the expression by canceling \(\cos x\) in numerator and denominator: \(-\left(\frac{\sin x}{\cos x}\right) \cos x = -\sin x\).
Conclude that the expression \(-\tan x \cos x\) is equivalent to \(-\sin x\), which can be matched to the corresponding expression in Column II.

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