Education Technology

# Knowledge Base

## Solution 12109: Accuracy Information for the TI-89 Family, TI-92 Family, and Voyage™ 200 Graphing Calculators.

### What is the computational and graphing accuracy for the TI-89 family, TI-92 family, and Voyage 200 graphing calculators?

Computational Accuracy

• Floating-point (decimal) values in memory are stored using up to 14 digits with a 3-digit exponent.
• For min and max Window variables (xmin, xmax, ymin, ymax, etc.), values using up to 12 digits can be stored. Other window variables use 14 digits.
• When a floating-point value is displayed, the displayed value is rounded as specified by the applicable mode settings (Display Digits, Exponential Format, etc.), with a maximum of 12 digits and 3-digit exponent.
• RegEQ displays up to 14-digit coefficients.
• Integer values in memory are stored using up to 614 digits.

Graphing Accuracy

• The Window variable xmin is the center of the leftmost pixel used, and xmax is the center of the rightmost pixel used. (delta)x is the distance between the centers of two horizontally adjacent pixels.
• (delta)x is calculated as (xmax-xmin)/(# of x pixels-1).
• If (delta)x is entered from the Home screen or a program, xmax is calculated as xmin + (delta)x*(# of x pixels-1).
• The window variable ymin is the center of the bottom pixel used, and ymax is the center of the top pixel used. (delta)y is the distance between the centers of two vertically adjacent pixels.
• (delta)y is calculated as (ymax-ymin)/(# of y pixels-1).
• If (delta)y is entered from the Home screen or a program, ymax is calculated as ymin+(delta)y*(# of y pixels-1).
• Cursor coordinates are displayed as eight characters (which may include a negative sign, decimal point, and exponent). The coordinate values (xc, yc, zc, etc.) are updated with a maximum of 12-digit accuracy.