Question

If sin x + sin^2 x = 1, then<br />cos^8 x + 2 cos^6 x + cos^4 x=<br />(A)0<br />(B) - 1<br />(C) 2<br />(D) 1​

Answer 1

Answer:

sinx+ sin^2 x=1

sinx(1+sinx)=1

Here,sinx=1

so,x=90°

And,1+sinx=1

sinx=0

so,x=0°