I'm going to assume this needs to be simplified:
1/(csctheta+1)-1/(csctheta-1)1cscθ+1−1cscθ−1
1/(1/sintheta+1)-1/(1/sintheta-1)11sinθ+1−11sinθ−1
1/(1/sintheta+sintheta/sintheta)-1/(1/sintheta-sintheta/sintheta)11sinθ+sinθsinθ−11sinθ−sinθsinθ
1/((1+sintheta)/sintheta)-1/((1-sintheta)/sintheta)11+sinθsinθ−11−sinθsinθ
sintheta/(1+sintheta)-sintheta/(1-sintheta)sinθ1+sinθ−sinθ1−sinθ
sintheta/(1+sintheta)((1-sintheta)/(1-sintheta))-sintheta/(1-sintheta)((1+sintheta)/(1+sintheta))sinθ1+sinθ(1−sinθ1−sinθ)−sinθ1−sinθ(1+sinθ1+sinθ)
(sintheta(1-sintheta))/((1+sintheta)(1-sintheta))-(sintheta(1+sintheta))/((1-sintheta)(1+sintheta))sinθ(1−sinθ)(1+sinθ)(1−sinθ)−sinθ(1+sinθ)(1−sinθ)(1+sinθ)
(sintheta-sin^2theta)/((1+sintheta)(1-sintheta))-(sintheta+sin^2theta)/((1-sintheta)(1+sintheta))sinθ−sin2θ(1+sinθ)(1−sinθ)−sinθ+sin2θ(1−sinθ)(1+sinθ)
(sintheta-sintheta-sin^2theta-sin^2theta)/((1+sintheta)(1-sintheta))sinθ−sinθ−sin2θ−sin2θ(1+sinθ)(1−sinθ)
(-2sin^2theta)/((1-sin^2theta))−2sin2θ(1−sin2θ)
Recall that sin^2theta+cos^2theta=1=>1-sin^2theta=cos^2thetasin2θ+cos2θ=1⇒1−sin2θ=cos2θ
(-2sin^2theta)/cos^2theta=-2tan^2theta−2sin2θcos2θ=−2tan2θ