Salam Academy
Paper 1 · Module

Trigonometry

5 subtopics≈ 215 min in total
  1. Exact values and the unit circle

    How sine, cosine and tangent are defined for any angle using the unit circle, the CAST rule for signs, and the exact values at 30∘30^\circ, 45∘45^\circ and 60∘60^\circ that you need without a calculator.

    ≈ 40 min
  2. Graphs and transformations

    The shapes of y=sin⁡xy=\sin x, y=cos⁡xy=\cos x and y=tan⁡xy=\tan x, their symmetries, and how aa, bb, cc and dd in y=asin⁡(b(x−c))+dy=a\sin(b(x-c))+d stretch and shift them. Then use the graphs to count solutions and model things that repeat.

    ≈ 45 min
  3. Inverse trigonometric functions

    Why sin⁡x=12\sin x=\tfrac12 has infinitely many solutions but sin⁡−112\sin^{-1}\tfrac12 has only one, the restricted domains that make sine, cosine and tangent one-to-one, and the principal values your calculator gives.

    ≈ 35 min
  4. Trigonometric identities

    The two identities at the heart of AS trigonometry, where they come from, and how to use them to simplify expressions, find exact values and write clear proofs.

    ≈ 40 min
  5. Solving trigonometric equations

    How to find every solution of a trig equation in an interval: principal value, symmetry, and period. Then equations with 2x2x or x+30∘x+30^\circ inside, quadratics in sin⁡x\sin x or cos⁡x\cos x, and equations that need an identity first.

    ≈ 55 min