OpenStax, Algebra and Trigonometry 2e §9.5 Solving Trigonometric Equations · Exercise 172 · Trigonometry · Identities

Solving Trigonometric Equations · Exercise 172

Find all exact solutions to the equation on $[0, 2 π) .$

Rewrite the expression as a product instead of a sum: $cos (2 x) + cos (- 8 x) .$

~8 minWritten answer · check your work with Lemma

OpenStax, Algebra and Trigonometry 2e · §9.5 Solving Trigonometric Equations · Exercise 172

Stuck? A gentle nudge

No hints for this one.

Something off?

Workspace

Your working

Check your full solution

Attach photos of your pages (up to 3) or one PDF — or check what you typed above. Lemma reads the work and verifies the reasoning, not just the answer.

Your first check today doesn't need an account.

Your photos and PDFs are read once and not stored — only the transcription is kept.