User Manual

Appendix B: Reference Information 398
Accuracy Information
Computational Accuracy
To maximize accuracy, the TI-84 Plus carries more digits internally than it displays. Values are
stored in memory using up to 14 digits with a two-digit exponent.
• You can store a value in the window variables using up to 10 digits (12 for
Xscl, Yscl, Tstep,
and q
step).
• Displayed values are rounded as specified by the mode setting with a maximum of 10 digits
and a two-digit exponent.
•
RegEQ displays up to 14 digits in Float mode. Using a fixed-decimal setting other than Float
causes
RegEQ results to be rounded and stored with the specified number of decimal places.
Xmin is the center of the leftmost pixel, Xmax is the center of the next-to-the-rightmost pixel. (The
rightmost pixel is reserved for the busy indicator.) @
X is the distance between the centers of two
adjacent pixels.
•In
Full screen mode, @X is calculated as (Xmax N Xmin) à 94. In G-T split-screen mode, @X is
calculated as (
Xmax N Xmin) à 46.
• If you enter a value for @
X from the home screen or a program in Full screen mode, Xmax is
calculated as
Xmin + @X É… 94. In G-T split-screen mode, Xmax is calculated as
Xmin + @X É… 46.
Ymin is the center of the next-to-the-bottom pixel; Ymax is the center of the top pixel. @Y is the
distance between the centers of two adjacent pixels.
•In
Full screen mode, @Y is calculated as (Ymax N Ymin) à 62. In Horiz split-screen mode, @Y is
calculated as (
Ymax N Ymin) à 30. In G-T split-screen mode, @Y is calculated as
(
Ymax N Ymin) à 50.
• If you enter a value for @
Y from the home screen or a program in Full screen mode, Ymax is
calculated as
Ymin + @Y É… 62. In Horiz split-screen mode, Ymax is calculated as
Ymin
+ @Y … 30. In G-T split-screen mode, Ymax is calculated as Ymin + @Y É … 50.
WINDOW RANGE A problem exists with the window variables.
• You defined Xmax  Xmin or Ymax  Ymin.
• You defined
qmax  qmin and qstep > 0 (or vice versa).
• You attempted to define
Tstep=0.
• You defined
Tmax  Tmin and Tstep > 0 (or vice versa).
• Window variables are too small or too large to graph correctly. You may have
attempted to zoom in or zoom out to a point that exceeds the TI-84 Plus’s
numerical range.
ZOOM • A point or a line, instead of a box, is defined in ZBox.
•A ZOOM operation returned a math error.
Error Type Possible Causes and Suggested Remedies