Respuesta :

cos^2x. hope this clarifies
Important relationships to note:

sec(x) = 1/cos(x)
cot(x) = 1/tan(x)
cosec(x) = 1/sin(x)

Thus, we can say:
sec(x) · tan(x) · sin(x) = [sin(x) · tan(x)]/cos(x)
= tan(x) tan(x)
= tan^2(x)