Question

if sin x + cos x = k then the value of 1 - sin 2x is​

Answer 1

Answer:

Step-by-step explanation:

sinx + cosx = 1,are given.

Then squaring on both side we get

(sinx + cosx)² =1²

=>sin²x +cos²x + 2sinx.cosx =1

Because (x+y)² = x² +y² + 2xy

=>1 + sin2x = 1, [because 2sin∅.cosx = sin2∅ ]

sin2x = 0

=>cos2x =±√(1-sin²2x)

=>cos2x = ±√(1–0)

Hence,cos2x = 1,–1, Ans.

I hope it helps you…!!!