(* Abbreviation: MathLib0 *)
(* Version 1.10, Nov 1984 *)
DEFINITION MODULE MathLib0;
(*
   Real Math Functions

From the book 'Programming in Modula-2' by Prof.
N. Wirth.
*)


EXPORT QUALIFIED
   sqrt, exp, ln, sin, cos, arctan, real, entier;


PROCEDURE sqrt(x: REAL): REAL;
(* 
- returns square root x

x must be positive.
*)


PROCEDURE exp(x: REAL): REAL;
(*
- returns e^x where e = 2.71828..
*)


PROCEDURE ln(x: REAL): REAL;
(*
- returns natural logarithm with base e = 2.71828.. of x

x must be positive and not zero
*)


PROCEDURE sin(x: REAL): REAL;
(*
- returns sin(x) where x is given in radians
*)


PROCEDURE cos(x: REAL): REAL;
(*
- returns cos(x) where x is given in radians
*)


PROCEDURE arctan(x: REAL): REAL;
(*
- returns arctan(x) in radians
*)


PROCEDURE real(x: INTEGER): REAL;
(*
- type conversion from INTEGER to REAL
*)

PROCEDURE entier(x: REAL): INTEGER;
(*
- returns the largest integer number less or equal x

Examples: entier(1.5) = 1; entier(-1.5) = -2;

If x cannot be represented in an INTEGER, the result is
undefined.
*)


END MathLib0.