Question

( sin x+sin ^{2} n=1 )
( sin x=1-sin ^{2} x )
( =int sin x=cos ^{2} x )
squandes
( Rightarrow sin ^{2} x=cos ^{4} x )
2) ( frac{1-cos ^{2} x}{cos ^{2} x+cos ^{4} x=1} cdot cos ^{4} x )

# 4. If sin x + sin?r=1 then the value of cosx+cos x = (a) 1 (b) 0 (C) -1 (d) 2

Solution