Appendix B: Reference Information
391
Important Things You Need to Know About Your TI-84 Plus
TI-84 Plus Results
There may be a number of reasons that your TI-84 Plus is not displaying the expected results;
however, the most common solutions involve order of operations or mode settings. Your calculator
uses an Equation Operating System™ (EOS™) which evaluates the functions in an expression in
the following order:
1. Functions that precede the argument, such as square root, sin(, or log(
2. Functions that are entered after the argument, such as exponents, factorial, r,
¡
, and
conversions
3. Powers and roots, such as 2^5, or 5*square root(32)
4. Permutations (nPr) and combinations (nCr)
5. Multiplication, implied multiplication, and division
6. Addition and subtraction
7. Relational functions, such as > or <
8. Logic operator and
9. Logic operators or and xor
Remember that EOS™ evaluates from left to right and calculations within parentheses are
evaluated first. You should use parentheses where the rules of algebra may not be clear. In OS
2.53 MP, parentheses may be pasted in an expression to indicate how the input is interpreted.
If you are using trigonometric functions or performing polar and rectangular conversions, the
unexpected results may be caused by an angle mode setting. The Radian and Degree angle mode
settings control how the TI-84 Plus interprets angle values.
To change the angle mode settings, follow these steps:
1. Press
z
to display the Mode settings.
2. Select
Degree
or
Radian
.
3. Press
Í
to save the angle mode setting.
where:
M
1
DT
1
Y
1
M
2
DT
2
Y
2
MB
DB
YB
=
=
=
=
=
=
=
=
=
month of first date
day of first date
year of first date
month of second date
day of second date
year of second date
base month (January)
base day (
1
)
base year (first year after leap year)
