1-20 Operating the TI-80
The Equation Operating System (EOS™) defines the order of operations for the
calculator
that is, the order in which the TI.80 evaluates functions in
expressions. EOS lets you enter numbers and functions in a simple,
straightforward sequence.
A function returns a value. EOS evaluates the functions in an
expression in the following order.
1Functions that are entered after the argument, such as
Añ, 2ê, 22!, 45¡, 2pô, and úSIMP.
2Powers and roots, such as 2^5 or 5õ‡32.
3Implied multiplication where the second argument is a
number, variable name, or list, or begins with an open
parenthesis, such as 4A, (A+B)4, or 4(A+B).
4Single-argument functions that precede the argument,
such as LA, ‡63, SIN B, or LOG 3.
5Implied multiplication where the second argument is a
multi-argument function or a single-argument function
that precedes the argument, such as 2NDERIV(Añ,A,6) or
ASIN 2.
6Permutations (nPr) and combinations (nCr).
7Multiplication and division (including INT÷).
8Addition and subtraction.
9Test functions, such as > or .
10 Conversion functions: 8FRAC, 8DEC, 8aÀbºc, and 8bºc.
Within a priority group, EOS evaluates functions from left to
right. However, two or more single-argument functions that
precede the same argument are evaluated from right to left.
For example, SIN FPART LN 8 is evaluated as
SIN(FPART(LN 8)).
Calculations within a pair of parentheses are evaluated first.
Multi-argument functions, such as NDERIV(Añ,A,6), are
evaluated as they are encountered.
The conversion functions 8FRAC, 8DEC, 8aÀbºc, and 8bºc
can be used only at the end of a command line with one
exception: they can be followed by a store instruction.
EOS (Equation Operating System)Order of
Evaluation