Hey guys, need help in a trig question.not sure which year it is is from.Here's how the question goes:
Using the expansion of cos(3x-x) and cos(3x+x) prove that:
1/2(cos2x - cos4x) = sin3x sinx
Its a 3 mark question so I'm pretty sure its not that complicated but I cant seem to get the answers.
Thanks in advance Smiley