Question

Which expression is equivalent to

(sin x + 1)(sin x − 1)?
A.)cos^2x
B.)-cos^2x
C.)cos^2x+ 1
D.)cos^2x − 1
E.)-cos^2x + 1

Answer 1

sin^2x -1 = -cos^2x.......

Answer 2

B.
sin^2x + cos^2x =1
hence Sin^2x-1 = - cos^2x