The Student Room Group

C3 a2 maths trig proof

Lol forgot to add the equation...
Could anyone tell me how to prove this/which is the right way to begin or anyway sort of system that you have to get the proof generally?
Sin^2x+3cos^2x=2+cos2x
(edited 7 years ago)
Original post by Hardy jacks
Could anyone tell me how to prove this/which is the right way to begin or anyway sort of system that you have to get the proof generally?


For what identity?
(edited 7 years ago)
Original post by Hardy jacks
Could anyone tell me how to prove this/which is the right way to begin or anyway sort of system that you have to get the proof generally?


In general, just try different ways, after loads of practise, you'll figure out the general patterns.
Original post by Hardy jacks
Could anyone tell me how to prove this/which is the right way to begin or anyway sort of system that you have to get the proof generally?

Many different ways for this now you may want to start with a 2 side length equilateral triangle and square of sides length 1 divided both by 2. And know your common angle table. The rest I don't see why you would ask this as they are always different unless a semicircle divided by two and you are told what to use
(edited 7 years ago)
Original post by Hardy jacks

Sin^2x+3cos^2x=2+cos2x


Well you can split the LHS into 2 identities by doing 3cos2(x)=cos2(x)+2cos2(x)3\cos^2(x)=\cos^2(x) + 2\cos^2(x)

Quick Reply

Latest