NAME
    sech - hyperbolic secant

SYNOPSIS
    sech(x [,eps])

TYPES
    x		real
    eps		nonzero real, defaults to epsilon()

    return	real

DESCRIPTION
    Calculate the sech of x to the nearest or next to nearest multiple of
    epsilon, with absolute error less than .75 * abs(eps).

    sech(x) = 2/(exp(x) + exp(-x))

EXAMPLE
    > print sech(1, 1e-5), sech(1, 1e-10), sech(1, 1e-15), sech(1, 1e-20)
    .64805 .6480542737 .648054273663885 .64805427366388539958

LIMITS
    unlike sin and cos, x must be real
    eps > 0

LIBRARY
    NUMBER *qsech(NUMBER *x, NUMBER *eps)

SEE ALSO
    sinh, cosh, tanh, csch, coth, epsilon