  
  
 	FUNCTIONS AVAILABLE TO THE BASIC USER
  
      Basic has a limited number of built in mathematical functions
 Those which do not exist directly can easily be defined using the
 DEFINE FUNCTION statement of BASIC.
  
 DEFINE FUNCTION STATEMENT
  
 DEF FN<letter> (list) = expression
 DEF FN<letter>%(list) = expression
 DEF FN<letter>$(list) = expression
  
 where:
  
 	<letter>	IS AN ALPHABETIC CHARACTER (A-Z)
 			THAT BECOMES PART OF THE FUNCTION NAME.
  
 	%		INDICATES THE FUNCTION RETURNS AN 
 			INTEGER VALUE.
  
 	$		INDICATES THAT THE FUNCTION RETURNS A
 			STRING VALUE
  
 	(list)		Contains from 1-5 dumy variables
 			(var1,var2,var3,var4,var5)
  
 	expression	is evaluated each time the function is
 			used.  It may contain any of the dumy
 			variables or any other variables in
 			the program.
  
 DEFINED FUNCTIONS
  
 SIN(expression)		expression is an angle in radians
 COS(expression)
 ATN(expression)
 PI			Returns the value of PI (3.14159)
  
 SQR(expression)		Returns the square root
  
 EXP(expression)		Returns the exponential function.
  
 LOG(exp)
 LOG10(exp)		Returns the natural and base 10 logarithm.
  
 INT(exp)		Returns the integer part of the expression.
  
 ABS(exp)		Returns the absolute value the expression.
  
 SGN(exp)		Returns +1 if the expression is 
 			positive, -1 if negative.
  
 RND			Gives a pseudo random number from 
 			0 to 1 each time it is used.  The
 			pseudo random numbers generated are
 			randomized further by executing a
 			RANDOMIZE statement within the program.
 			If this were not done the random numbers
 			generated each time the program is run
 			would be the same.
  
  
  
 USEFUL EXPRESSIONS   (where E  is any expression)
  
 TAN(E) = SIN(E)/COS(E)
 SEC(E) = 1/COS(E)
 CSC(E) = 1/SIN(E)
 COT(E) = COS(E)/SIN(E)
 ASIN(E) = ATN(E/SQR(1-E*E))
 ACOS(E) = ATN(SQR(1-E*E)/E)
 ASEC(E) = ATN(SQR(E*E-1))
 ACSC(E) = ATN(1/SQR(E*E-1))
 ACTN(E) = ATN(1/E)
 SINH(E) = (EEP(E)-EEP(-E))/2
 COSH(E) = (EEP(E)+EEP(-E))/2
 TANH(E) = (EEP(E)-EEP(-E))/(EEP(E)+EEP(-E))
 ASINH(E) =LOG(E+SQR(E*E+1))
 ACOSH(E) = LOG(E+SQR(E*E-1))
 ATANH(E) = (LOG(1+E) - LOG(1-E))/2
