Trigonometry 2: expressions and identities

AS Level

  • Understand and use tanθ=sinθ/cosθ
  • Understand and use sin^2θ+cos^2θ = 1
  • Solve simple trigonometric equations in a given interval, including quadratic equations in sin, cos and tan and equations involving multiples of the unknown angle

A Level

  • Sec2 θ = 1 + tan2θ  and cosec2θ = 1 + cot2θ
  • Understand and use double angle formulae; use of formulae for sin(A±B), cos(A±B) and tan(A±B)
  • Understand geometrical proofs of these formulae
  • Understand and use expressions for acosθ + bsinθ in the equivalent forms of rcos(θ±α) or sin(θ±α)
  • Construct proofs involving trigonometric functions and identities
  • Use trigonometric functions to solve problems in context, including problems involving vectors, kinematics and forces