IB DP Maths: AA HL复习笔记3.6.6 Quadratic Trigonometric Equations

How are quadratic trigonometric equations solved?

• A quadratic can give up to two solutions
  • You must consider both solutions to see whether a real value exists
  • Remember that solutions for sin θ = k and cos θ = k only exist for -1 ≤ k ≤ 1
  • Solutions for tan θ = k exist for all values of k
• Find all solutions within the given interval
  • There will often be more than two solutions for one quadratic equation
  • The best way to check the number of solutions is to sketch the graph of the function