Trigonometry

Trigonometry

Defining Trigonometric Functions

  • Understand sine (sin), cosine (cos), and tangent (tangent) as ratios of the sides in a right-angled triangle.
  • Illustrate the definition of trigonometric functions on the unit circle, where radius = 1.
  • Apply the SOHCAHTOA mnemonic to remember the definitions of sin, cos, and tan.

Trigonometric Identities

  • Comprehend the Pythagorean Identity, which is sin²x + cos²x = 1.
  • Recognise that tanx is equivalent to sinx/cosx.
  • Understand and apply the double angle formulae for sin2x, cos2x and tan2x.
  • Implement the reciprocal identities: secx=1/cosx, cscx=1/sinx, cotx=1/tanx.

Solving Trigonometric Equations

  • Solve basic trigonometric equations for given intervals, using radian and degree measures.
  • Make use of standard results to solve trigonometric equations involving multiples of 30° or 45° or 60° or 90°.
  • Use trigonometric identities to simplify and solve more complex equations.
  • Understand how to sketch the trigonometric functions and use these sketches to solve associated equations.

Trigonometric Values of Special Angles

  • Memorise the exact values of sin, cos and tan for 0°, 30°, 45°, 60° and 90°.
  • Use symmetries of the trigonometric functions to identify corresponding values for angles over 90°.

Trigonometric Applications

  • Utilise trigonometry to find distances and angles in right-angled triangles.
  • Apply trigonometry to solve practical problems involving angles of elevation and depression.
  • Comprehend and calculate the area of a triangle using 1/2absinC.
  • Use the sine and cosine rules to solve problems involving non-right angled triangles.

Trigonometric Graphs

  • Understand how to graph y=sinx, y=cosx, and y=tanx.
  • Identify the amplitude, period, phase, and shifts for the given trigonometric graphs.
  • Understand the effect of changing the coefficient of x on these graphs.