tanθ+secθ−1tanθ−secθ+1=
1−cosθsinθ
1−sinθcosθ
1+cosθsinθ
1+sinθcosθ
tanθ+secθ−1tanθ−secθ+1= tanθ+secθ−(sec2θ−tan2θ)tanθ−secθ+1
=(tanθ+secθ)(1−secθ+tanθ)tanθ−secθ+1
=tanθ+secθ
=1+sinθcosθ