Question

Sec 75° equals to _____

(a) cosec 15°

(b) sec 15°

(c) 1

(d) 0

I had been asked this question by my college professor while I was bunking the class.

This is a very interesting question from Trigonometric Ratios of Complementary Angles topic in portion Trigonometry of Mathematics – Class 10

Answer 1

Right answer is (a) cosec 15°

Explanation: All trigonometric ratios are positive in the first quadrant and secant changes to cosecant when it is 90° or 270°.

Sec 75° = Sec (90° – 15°)

= Cosec 15°