Question

Sin theta +cos theta=1 find the value of the 2sin theta-cos theta

Answer 1

let sin theta be x

let cos theta be your

so, x+y=1

there is only one possibility,that is

one of x,y is 0 and the other is 1

let x=0 so, y=1

sin theta =0 and cos theta =1 is only possible when theta = 0

so theta =0

now 2 sin theta - cos theta with theta = 0 will be,

2 sin 0- cos 0

2(0)-1=-1