Find the exact value of the real number y. y = arcsec (-1)

Secant is a trigonometric function that quantifies the quotient of hypotenuse and the side that is adjacent to the given angle. This is the reciprocal of the cosine function.

cosine = adjacent / hypotenuse = x/h

secant = h / x

Secant equal to - 1 means that x and h are numerically equal but opposite in sign.

secant = - 1

cosine = 1/secant = 1/-1 = - 1

arccos (-1) = 180°

Thus, the answer to this item is 180°.