Answer:
tan²x
Step-by-step explanation:
Using the Pythagorean identity
sin²x + cos²x = 1
Divide all terms by cos²x
[tex]\frac{sin^2x}{cos^2x}[/tex] + [tex]\frac{cos^2x}{cos^2x}[/tex] = [tex]\frac{1}{cos^2x}[/tex], that is
tan²x + 1 = sec²x ( subtract 1 from both sides )
tan²x = sec²x - 1