(* Math -- SML Basis Library *) type real = real val pi    : realval e     : real val sqrt  : real -> realval sin   : real -> realval cos   : real -> realval tan   : real -> realval atan  : real -> realval asin  : real -> realval acos  : real -> realval atan2 : real * real -> realval exp   : real -> realval pow   : real * real -> realval ln    : real -> realval log10 : real -> realval sinh  : real -> realval cosh  : real -> realval tanh  : real -> real (*     [pi] is the circumference of the circle with diameter 1, that is,   3.14159265358979323846.    [e] is the base of the natural logarithm: 2.7182818284590452354.    [sqrt x] is the square root of x.  Raises Domain if x < 0.0.    [sin r] is the sine of r, where r is in radians.    [cos r] is the cosine of r, where r is in radians.    [tan r] is the tangent of r, where r is in radians.  Raises Domain if    r is a multiple of pi/2.    [atan t] is the arc tangent of t, in the open interval ] ~pi/2, pi/2 [.    [asin t] is the arc sine of t, in the closed interval [ ~pi/2, pi/2 ].     Raises Domain if abs x > 1.    [acos t] is the arc cosine of t, in the closed interval [ 0, pi ].   Raises Domain if abs x > 1.    [atan2(y, x)] is the arc tangent of y/x, in the interval ] ~pi, pi ],   except that atan2(y, 0) = sign y * pi/2.  The quadrant of the result   is the same as the quadrant of the point (x, y).   Hence sign(cos(atan2(y, x))) = sign x    and   sign(sin(atan2(y, x))) = sign y.     [exp x] is e to the x'th power.    [pow (x, y)] is x it the y'th power, defined when       y >= 0 and (y integral or x >= 0)   or y < 0 and ((y integral and x <> 0.0) or x > 0).    We define pow(0, 0) = 1.    [ln x] is the natural logarithm of x (that is, with base e).   Raises Domain if x <= 0.0.    [log10 x] is the base-10 logarithm of x.  Raises Domain if x <= 0.0.    [sinh x] returns the hyperbolic sine of x, mathematically defined as   (exp x - exp (~x)) / 2.  Raises Overflow if x is too large.    [cosh x] returns the hyperbolic cosine of x, mathematically defined as   (exp x + exp (~x)) / 2.  Raises Overflow if x is too large.    [tanh x] returns the hyperbolic tangent of x, mathematically defined    as (sinh x) / (cosh x).  Raises Domain if x is too large.*)