HP 40gs - Manual (Page 171)

Using mathematical functions 13-17
Examples
SIGN (–2) returns –1
SIGN((3,4)) returns (.6,.8)
TRUNCATE Truncates value to decimal places. Accepts complex
numbers.
TRUNCATE(value, places)
Example
TRUNCATE(2.3678,2) returns 2.36
XPON Exponent of value.
XPON(value)
Example
XPON(123.4) returns 2
Two-variable statistics
These are functions for use with two-variable statistics.
See “Two-variable” on page 10-15.
Symbolic functions
The symbolic functions are used for symbolic
manipulations of expressions. The variables can be
formal or numeric, but the result is usually in symbolic
form (not a number). You will find the symbols for the
symbolic functions = and | (where) in the CHARS menu
(
CHARS ) as well as the MATH menu.
= ( equals ) Sets an equality for an equation. This is not a logical
operator and does not store values. (See “Test functions”
on page 13-19.)
expression1=expression2
ISOLATE Isolates the first occurrence of variable in expression=0
and returns a new expression, where
variable=newexpression. The result is a general solution
that represents multiple solutions by including the (formal)
variables S1 to represent any sign and n1 to represent
any integer.
ISOLATE(expression, variable)
hp40g+.book Page 17 Friday, December 9, 2005 1:03 AM