The question is

a) show that the equation

2sin²x – cosx = 1

can be written as

2cos²x + cosx – 1 =0

b) using your answer to part (a), find all the solutions of the equation

2sin²x – cosx = 1

in the interval 0 < x < 2ð, giving your answer in the terms of ð

the funny ð is supposed to be pi

my working so far to follow