2 asin - inverse trigonometric sine
9 eps nonzero real, defaults to epsilon()
14 Returns the asin of x to a multiple of eps with error less in
15 absolute value than .75 * eps.
17 v = asin(x) is the number in [-pi/2, pi/2] for which sin(v) = x.
20 > print asin(.5, 1e-5), asin(.5, 1e-10), asin(.5, 1e-15), asin(.5, 1e-20)
21 .5236 .5235987756 .523598775598299 .52359877559829887308
27 NUMBER *qasin(NUMBER *q, NUMBER *epsilon)
30 acos, atan, asec, acsc, acot, epsilon