Question

if cos 0 + sin 0 = 2 cos 0 .show that ( cos 0- sin 0) = 2 sin 0​

Answer 1

Answer:

Given

cosθ+sinθ=

2

cosθ

squaring on both the sides, we get,

cos

2

θ+sin

2

θ+2sinθcosθ=2cos

2

θ

cos

2

θ−sin

2

θ=2cosθsinθ

(cosθ+sinθ)(cosθ−sinθ)=2cosθsinθ

2

cosθ(cosθ−sinθ)=2cosθsinθ [ Given cosθ+sinθ=

2

cosθ]

∴cosθ−sinθ=

2

sinθ [henceproved]