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Unit 4 · 10 lessons

Trigonometric Functions

From right-triangle trig through the sine and cosine laws to sinusoidal graphs and real-world modelling — all in degrees.

  • 113 practice questions
  • 89 flashcards
  • 3 interactive lessons
Start lesson 1 →Unit 4 test review →

Lessons

  1. 1Right Triangle TrigonometrySOH CAH TOA lets you find a missing side or angle in any right triangle, and angles of elevation/depression are the most common way this shows up in word problems.11 questions
  2. 2Special Triangles and Exact ValuesThe 30-60-90 and 45-45-90 triangles produce exact (non-decimal) trig ratios you're expected to know without a calculator, and they preview the unit-circle idea.Interactive11 questions
  3. 3Angles from 0° to 360° and the CAST RuleExtend sine, cosine, and tangent beyond acute angles using reference angles and the CAST rule for signs, including negative angles and reciprocal ratios.Interactive11 questions
  4. 4The Sine LawSOH CAH TOA only works in right triangles — the sine law extends triangle-solving to ANY triangle, whenever you have a matched angle/side pair.11 questions
  5. 5The Ambiguous Case of the Sine Law (SSA)Given two sides and a non-included angle, a triangle might not be uniquely determined — there could be zero, one, or two valid triangles. Learn the test to tell which.11 questions
  6. 6The Cosine LawWhen the sine law can't get started (SAS or SSS), the cosine law solves the triangle instead — and rearranges cleanly to find any missing angle.12 questions
  7. 7Trigonometric IdentitiesThe Pythagorean and quotient identities are algebraic relationships between sin, cos, and tan that hold for every angle — and proving identities is an algebra skill dressed up in trig notation.11 questions
  8. 8Periodic Functions: Period, Amplitude, and AxisBefore graphing sinusoids, learn the vocabulary that describes ANY repeating pattern — period, amplitude, the equation of the axis, and maximum/minimum values.12 questions
  9. 9Graphs of y = sin x and y = cos x — TransformationsThe parent sine and cosine curves, and how , , , and in stretch, compress, shift, and reflect them.Interactive11 questions
  10. 10Modelling with Sinusoidal FunctionsFerris wheels, tides, daylight hours, and temperature all repeat in a roughly sinusoidal pattern — learn to translate a real description into an equation.12 questions