## Algebra and Trigonometry 10th Edition

The identity is verified. $(sec~θ+tan~θ)(sec~θ-tan~θ)=1$
Use: $1+tan^2θ=sec^2θ$ $1=sec^2θ-tan^2θ$ $(sec~θ+tan~θ)(sec~θ-tan~θ)=sec^2θ-tan^2θ=1$