Question

Which expression is equivalent to sec2x − 1?

Answer 1

Answer:

tan²x

Step-by-step explanation:

Using the Pythagorean identity

sin²x + cos²x = 1

Divide all terms by cos²x

$\frac{sin^2x}{cos^2x}$ + $\frac{cos^2x}{cos^2x}$ = $\frac{1}{cos^2x}$, that is

tan²x + 1 = sec²x ( subtract 1 from both sides )

tan²x = sec²x - 1