Question

PLEASE HELP (100 POINTS)

Answer 1

I have done this questions before, the answer is C

Explanation:

Answer 2

`\\ \rm\Rrightarrow 2sin^2x=1-cosx`

`\\ \rm\Rrightarrow 2sin^2x=1-1+sin^2x`

`\\ \rm\Rrightarrow 2sin^2x-sin^2x=0`

`\\ \rm\Rrightarrow sin^2x=0`

`\\ \rm\Rrightarrow sinx=0`

`\\ \rm\Rrightarrow x\in n\pi`