Texas Instruments TINSPIRE Reference Guide - Page 141

EOS™ (Equation Operating System) hierarchy This section describes the Equation Operating System (EOS™) that is used by the TI-Nspire™ math and science learning technology. Numbers, variables, and functions are entered in a simple, straightforward sequence. EOS™ software evaluates expressions and equations using parenthetical grouping and according to the priorities described below. Order of evaluation Level 1 2 3 4 Operator Parentheses ( ), brackets [ ], braces { } Indirection (#) Function calls Post operators: degrees-minutes-seconds (¡,',"), factorial (!), percentage (%), radian Q( RS), subscript ([ ]), transpose (T) 5 Exponentiation, power operator (^) 6 L Negation ( ) 7 String concatenation (&) 8 Multiplication (†), division (/) 9 Addition (+), subtraction (-) 10 Equality relations: equal (=), not equal (ƒ or /=), less than (=) 11 Logical not 12 Logical and 13 Logical or, exclusive logical xor 14 Constraint "with" operator (|) 15 Store (&) Parentheses, brackets, and braces All calculations inside a pair of parentheses, brackets, or braces are evaluated first. For example, in the expression 4(1+2), EOS™ software first evaluates the portion of the expression inside the parentheses, 1+2, and then multiplies the result, 3, by 4. The number of opening and closing parentheses, brackets, and braces must be the same within an expression or equation. If not, an error message is displayed that indicates the missing element. For example, (1+2)/(3+4 will display the error message "Missing )." Note: Because the TI-Nspire™ software allows you to define your own functions, a variable name followed by an expression in parentheses is considered a "function call" instead of implied multiplication. For example a(b+c) is the function a evaluated by b+c. To multiply the expression b+c by the variable a, use explicit multiplication: a∗(b+c). TI-Nspire™ Reference Guide 135