. The Secant Function and Inverse Secant Function The secant function is defined as the reciprocal of cosine function. So, y sec is defined for all values of x except when cos x = .Thus, the domain of the function y = sec is \ ( : ∈ . As −≤ cos x , y = sec does not take values in ( , ) - .
Thus, the range of the secant function is ( , ] [ , −∞ ∪ ∞ . The secant function has neither maximum nor minimum. The function y = sec is a periodic function with period p and it is also an even function. y π y π O y y O - π y = cosec – x y = cosec x in \ { } é ë êê ù û úú π π Inverse - -