How do you verify (1+cosx)(1-cosx) = sin^2 x?

2 Answers

See proof below

Explanation:

Notice, \sin^2x+\cos^2x=1

Now, consider LHS, as follows

LHS=(1+\cos x)(1-\cos x)

=1^2-(cos x)^2

=1-\cos^2x

=\sin^2 x

=RHS

Proved.

Jul 27, 2018

"see explanation"

Explanation:

"using the "color(blue)"trigonometric identity"

•color(white)(x)sin^2x+cos^2x=1

"consider the expansion of the left side"

1cancel(-cosx)cancel(+cosx)-cos^2x

=1-cos^2x

=sin^2x=" right side "rArr"verified"