Final answer:
The expression (tan A * cos² A) / sec A simplifies to sin A by using trigonometric identities to replace tan A and sec A with sin A / cos A and 1 / cos A, respectively, and then canceling out the common terms.
Step-by-step explanation:
To express the expression (tan A * cos² A) / sec A in terms of sin A, we can use trigonometric identities.
First, we know that tan A is equal to sin A / cos A and that sec A is equal to 1 / cos A. Plugging these into the expression, we get:
(
(sin A / cos A) * cos² A
) / (
1 / cos A
)
Now we can simplify the expression:
(sin A * cos A * cos A) / (1 / cos A)
= sin A * cos² A * cos A
= sin A * cos A
Since cos A multiplied by itself is cos² A, and we have a cos A in the numerator and denominator, they cancel out, leaving us with:
sin A
Thus, the expression (tan A * cos² A) / sec A simplifies to sin A, which corresponds to option A.