Study Guide
Learning Objectives
- Rewrite with Pythagorean identity and derived forms (3.12.A.1-A.2).
- Use sine/cosine sum, difference, and double-angle identities (3.12.B.1-B.3).
- Verify identities algebraically (3.12.B.4).
- Solve using equivalent analytic representations (3.12.C.1-C.2).
Suggested Practice Sequence
1. Memorize and apply sin^2 + cos^2 = 1. 2. Derive tan/sec and cot/csc forms. 3. Practice sin/cos sum; derive difference and double-angle. 4. Verify simple identities step by step. 5. Rewrite equations, then solve on an interval (with 3.10).
Classroom / Check-In Moves
- "Which identity?" decision before algebra.
- One verification with substitution.
- Domain note when dividing by trig functions.
Misconception Watch-List
- sin(A+B) vs sin A + sin B.
- Wrong sign in cos sum.
- Forgetting +/- double-angle options for cos(2A).
- Skipping equivalence justification on FRQ.
Vocabulary to Own
- Pythagorean identity; equivalent form
- sum; difference; double-angle
- verify; simplify; substitute
- domain restriction
Materials Map
- Practice: identities, verify, rewrite-to-solve
- Word: applied simplification/solving
- Mixed / multi-*: link 3.9-3.11, 3.10
- Review & practice test: identity fluency
- Interactive: identity and rewrite checks