Maths

I completely stuck on trig equations. Can anyone help me please by doing a couple of these. They are all solving an equation.
Sin2x =sinx.
3cos2x=2cos²x
cos2x=1-cosx

Thanks Amanda

Reply 1

Tulipbloom

Original post by AZHere20

I completely stuck on trig equations. Can anyone help me please by doing a couple of these. They are all solving an equation.
Sin2x =sinx.
3cos2x=2cos²x
cos2x=1-cosx
Thanks Amanda

Think you should try solving em but I'll give you a clue: all questions require the double angle formula. Lemme know if you get stuck.

Reply 2

AZHere20

Hi Tulipbloom
Thanks for your encouragement. I have managed to do them now but it's taken me 3hours to do them. Would you be happy to help me with some others. I'm really struggling. I've made a start on them all but don't know how to finish them.
À. 3cosX -sinX/2-1=0
I've divided it all by cosX and multiplied by 2 and got 6 - tanx -1 but I'm not sure if that is correct or what to do next.

B. 2sinX =secX
Ive got this far.
2sin(cos) =1

Thanks