Show That the Equation Is Not an Identity by Finding $\cos 2 x + \cos 6 x = 2 \cos 4 x \cos x$

question 72

Multiple Choice

Show that the equation is not an identity by finding a value of x for which both sides are defined but not equal.
- $\cos 2 x + \cos 6 x = 2 \cos 4 x \cos x$

• A) \(\frac { \pi } { 4 }\)
• B) 0
• C) \(2 \pi\)
• D) \(- 2 \pi\)

---

Definitions:

Punctuated Correctly

Marked with appropriate punctuation marks, ensuring clarity and proper reading structure.

Conjunctions

Words used to connect clauses, sentences, or words in the same clause, playing a crucial role in building complex sentences and ensuring coherence in speech and writing.

Conjunctive Adverbs

Adverbs that connect clauses or sentences, showing relationship in terms of cause, contrast, time, or sequence (e.g., however, therefore, moreover).

Punctuated Correctly

Refers to texts that have been structured and marked using proper punctuation marks.