Which transformation was applied to triangle A? A transformation is applied to the smaller triangle, A, to
form the larger triangle, B.
Which transformation was applied to triangle A?

dilation
reflection
rotation
translation

Working with the right side,

(1 + sin(θ))/(1 - sin(θ)) - (1 - sin(θ))/(1 + sin(θ))

multiply the first term by (1 + sin(θ))/(1 + sin(θ)) and the second one by (1 - sin(θ))/(1 - sin(θ)). This gives

(1 + sin(θ))/(1 - sin(θ)) • (1 + sin(θ))/(1 + sin(θ)) = (1 + sin(θ))^2 / (1 - sin^2(θ))

… = (1 + sin(θ))^2 / cos^2(θ)

and

(1 - sin(θ))/(1 + sin(θ)) • (1 - sin(θ))/(1 - sin(θ)) = (1 - sin(θ))^2 / (1 - sin^2(θ))

… = (1 - sin(θ))^2 / cos^2(θ)

Now combine the fractions, expand the numerator, and simplify:

(1 + sin(θ))^2 / cos^2(θ) - (1 - sin(θ))^2 / cos^2(θ) = ((1 + sin(θ))^2 - (1 - sin(θ))^2) / cos^2(θ)

… = ((1 + 2 sin(θ) + sin^2(θ)) - (1 - 2 sin(θ) + sin^2(θ))) / cos^2(θ)

… = 4 sin(θ) / cos^2(θ)

… = 4 • sin(θ)/cos(θ) • 1/cos(θ)

… = 4 tan(θ) sec(θ)