HP Prime Graphing Calculator - Manual (Page 402)

396 Functions and commands
id Returns a vector containing the solution to the identity function
for the argument(s).
id(Object1, [Object2,…])
Example:
id([1 2], 3, 4) returns [[1 2] 3 4]
identity Given an integer n, returns the identity matrix of dimension n.
identity(Integer)
Example:
identity(3)
returns
iegcd Returns the extended greatest common divisor of two integers.
iegcd(Integer1, Integer2)
Example:
iegcd(14, 21)
returns
[-1, 1, 7]
igcd Returns the greatest common divisor of two integers or two
rational numbers or two polynomials of several variables.
igcd((Integer1, Integer2) or
igcd(Ratnl1, Ratnl2) or
igcd(Poly1, Poly2)
Examples:
igcd(24, 36) returns 12
igcd(2/3,3/4) returns 1/12
interval2center Returns the center of an interval.
interval2center(Interval)
Example:
interval2center(2..5)
returns
7/2
inv Returns the inverse of an expression or matrix.
inv(Expr) or inv(Matrix)
Example:
inv(9/5)
returns
5/9
1 0 0
0 1 0
0 0 1