2 sec - trigonometric secant function
9 eps nonzero real, defaults to epsilon()
14 Calculate the secant of x to a multiple of eps, with error less
15 in absolute value than .75 * eps.
18 > print sec(1, 1e-5), sec(1, 1e-10), sec(1, 1e-15), sec(1, 1e-20)
19 1.85082 1.8508157177 1.850815717680926 1.85081571768092561791
22 unlike sin and cos, x must be real
26 NUMBER *qsec(NUMBER *x, NUMBER *eps)
29 sin, cos, tan, csc, cot, epsilon