Question

cos 2x = cos^2x - sin^2x = 2 cos^2x-1=1-2sin^2x= 1-tan^2x/1+tan^2x.......to prove....

Answer 1

cos2x=cos(x+x)
=cosx×cosx-sinx×sinx
=cos^2x-sin^2x
cos2x=cos^2x-sin^2x
=cos^2x-1+cos^2x
=2cos^2x-1
cos2x=cos^2x-sin^2x
=1-sin^2x-sin^2x
1-2sin^2x

Answer 2

Answer:

Step-by-step explanation:

cos2x=cos(x+x)

=cosx×cosx-sinx×sinx

=cos^2x-sin^2x

cos2x=cos^2x-sin^2x

=cos^2x-1+cos^2x

=2cos^2x-1

cos2x=cos^2x-sin^2x

=1-sin^2x-sin^2x

1-2sin^2x

Hope this helps u

Please make it brainlist