Let's take a look at a typical Core 2 question on solving trignomentric equations.
This is part (b), where part (a) asks you to show that the equation can be rewritten as
(1 - 5 cos 2x)( sin 2x) = 0.
A few exam tips when answering these:
1. Which trig identity should I use to simplify the equation? Is it a quadratic (using sine squared or cosine squared) or not?
2. Has the equation been factorised already? Can I see multiple solutions? Remember that if you square root, you need to use a positive and negative root.
3. Remember to find the range for 2x, or whichever function of x you find by removing the trig function.
4. Use a quick sketch of a trigonometric graph to help you remember how many solutions are in this range.
You can find worked solutions to this question,
here for part a and
here for part b.
There's plenty more exam questions where that came from - take a look at
exam solutions, which can link you straight to this type of question for each past paper.
