The secant of an angle is the reciprocal of the cosine of an angle. On the unit circle, the secant of an angle is equal to the hypotenuse of a right-triangle with an adjacent side of length .

The graph of the secant and cosine is a visual way to remember which function that secant is the reciprocal of. As the cosine function approaches so does secant and as the cosine function approaches the secant function diverges to infinity.