DeepIdentities

Gilbert Strang, Calculus, 3rd edition (Wellesley-Cambridge Press; MIT OpenCourseWare RES.18-001) §1.5 A Review of Trigonometry, #31 · Trigonometry · Identities

Draw the base of a triangle from the origin … to

Draw the base of a triangle from the origin $O = (0, 0)$ to $P = (a, 0)$ . The third corner is at $Q = (b cos θ, b sin θ)$ . What are the side lengths $O P$ and $O Q$ ? From the distance formula (1) show that the side $P Q$ has length
$d^{2} = a^{2} + b^{2} - 2 ab cos θ (law of cosines) .$

~11 minWritten answer · check your work with Lemma

Gilbert Strang, Calculus, 3rd edition (Wellesley-Cambridge Press; MIT OpenCourseWare RES.18-001) · §1.5 A Review of Trigonometry, #31

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.