Question

Given the identity tanX=sinXcosX and the relationship between the sine and cosine of complementary angles, what is tan (90°− A)?

A) 1cosA

B) 1sinA

C) 1tanA

D) sinAcosA

Answer 1

tan (90 - A) = sin (90 - A) / cos (90 - A) = (sin 90 cos A - sin A cos 90)/(cos 90 cos A + sin 90 sin A) = cos A / sin A = 1 / (sin A / cos A) = 1/tan A