Strategy for Further Trigonometric Equations (Edexcel A Level Maths): Revision Note
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Strategy for Further Trigonometric Equations
How to approach solving harder trig equations
You can solve harder trig equations, such as those involving reciprocal and inverse functions in a variety of different ways
Using further trigonometric identities
Using compound or double angle formulas
Factorising quadratic trig equations
Then finding all solutions using CAST or sketching graphs
The final rearranged equation you solve will involve sin, cos or tan – don’t try to solve an equation with cosec, sec, or cot directly
If you’re having trouble solving a trig equation, this flowchart might help:
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Examiner Tips and Tricks
Try to use identities and formulas to reduce the equation into its simplest terms.
Don’t forget to check the function range and ensure you have included all possible solutions.
If the question involves a function of x or θ ensure you transform the range first (and ensure you transform your solutions back again at the end!).
Worked Example
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