Question

multiply and write the left side expression as the difference of two squares. sec²θ - 1
the expression from the previous step is equivalent to tan²θ using what?
a. quotient identity
b. even - odd identity
c. pythagorean identity
d. cancellation property
e. reciprocal identity

Explanation:

The Pythagorean identity in trigonometry states that $\sec^{2}\theta=1 + \tan^{2}\theta$. Rearranging this identity gives $\sec^{2}\theta - 1=\tan^{2}\theta$.

Answer:

C. Pythagorean Identity