How do you verify csc^2 θ + sec^2 θ = csc^2 θsec^2 θ?

1 Answer
Aug 10, 2018

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