HP 48g Graphing Calculator - Manual (Page 136)

11
Remember: Unless you surround functions in single-quotes (the ' ‘
tick-mark delimiters), the HP 48 assumes that you are using postfix
syntax whenever you invoke the name of a function and thus uses
(or attempts to use) objects from the stack as the arguments for the
function.
Expressions and Equations
An expression is an algebraic that does not contain an = function.
An equation is an algebraic that does contain an = function. For
example, ' :31H (b! > - ATAH < > +6*X ' is an expression, and
' Y=HTAH(£*b:)+6*X ‘ is an equation.
When you use an equation as the argument of a function, the function
is applied to both sides, and the result is also an equation. For
example, ' Y=Y ' SIN returns ' SIN (X ) =S IN ( Y > '.
In the HP 48, = generally means equating two expressions. The
DEFINE command (fi^fDEF)) interprets = differently—it stores the
expression on the right side of the equal sign in the name on the left
side (see 11-7 for more details).
Symbolic Constants
The HP 48 has five built-in constants that can be included in algebraic
expressions either as symbolic constants or as 12-digit numerical
approximations. The five constants are these:
■ 7T (:3, 14159265359), the ratio of a circle’s perimeter to its
diameter.
B e (2.71828182846), the natural logarithm base.
B I ((0, 1 >), the square root of (-1).
B MAXR (9.99999999999E499), the largest positive real number
representable by the HP 48.
fl MINR (1. E-499), the smallest positive real number representable
by the HP 48.
The five constants are available in both symbolic and numeric forms
in the MTH CONSTANTS menu, accessed by pressing
( M T H ) ( N X T )
C 0 N 8 . Three of the constants can also be entered directly from the
main keyboard:
11-4 Using Mathematical Functions