How do you simplify the expression (1-tan^2t)/(1+tan^2t)+1?

1 Answer
Oct 11, 2016

=(1 - sin^t/cos^2t)/(1 + sin^2t/cos^2t) + 1

=((cos^2t - sin^2t)/cos^2t)/((cos^2t + sin^2t)/(cos^2t)) + 1

=(cos^2t - sin^2t)/(cos^2t) xx cos^2t/(cos^2t + sin^2t)

Apply the identity sin^2theta + cos^2theta = 1.

=cos^2t - sin^2t

=1 - sin^2t - sin^2t

= 1 - 2sin^2t

Apply the double angle identity cos2theta = 1 - 2sin^2theta.

=cos2t

Hopefully this helps!