Question #ccc87

1 Answer
Sep 22, 2016

cosθ1+sinθ+1+sinθcosθ

=cosθ(1sinθ)(1sinθ)(1+sinθ)+1+sinθcosθ

=cosθ(1sinθ)1sin2θ+1+sinθcosθ

=cosθ(1sinθ)cos2θ+1+sinθcosθ

=1sinθcosθ+1+sinθcosθ

=1cosθsinθcosθ+1cosθ+sinθcosθ

=2cosθ=2secθ

Alternative

cosθ1+sinθ+1+sinθcosθ

=cos2θ+(1+sinθ)2(1+sinθ)cosθ

=cos2θ+(1+2sinθ+sin2θ)(1+sinθ)cosθ

=2+2sinθ(1+sinθ)cosθ

=2cosθ=2secθ