csc^2 θ + sec^2 θ = csc^2 θsec^2 θ
Since 1+tan^2theta=sec^2theta:
csc^2 θ + sec^2 θ = csc^2 θ(1+tan^2theta)
csc^2 θ + sec^2 θ = csc^2 θ+csc^2thetatan^2theta
Since csctheta=1/sintheta and tantheta=sintheta/costheta:
csc^2 θ + sec^2 θ = csc^2 θ+1/sin^2theta*sin^2theta/cos^2theta
csc^2 θ + sec^2 θ = csc^2 θ+1/cancel(sin^2theta)*cancel(sin^2theta)/cos^2theta
csc^2 θ + sec^2 θ = csc^2 θ+1/cos^2theta
Since sectheta=1/costheta:
csc^2 θ + sec^2 θ = csc^2 θ+sec^2theta sqrt