Shading of inequalities on a graphing calculator

• US 6,771,252 B2
• Filed: 12/20/2000
• Issued: 08/03/2004
• Est. Priority Date: 12/20/2000
• Status: Active Grant

• Current Assignee: Texas Instruments, Inc.
• Original Assignee: Texas Instruments, Inc.
• Inventors: Zhang, Jian, Miller, Michelle A.
• Primary Examiner(s): Shankar, Vijay
• Assistant Examiner(s): Dharia, Prabodh M.
• Application Number:
  US09/742,864
• Publication Number:
  US 20020075265A1
• Time in Patent Office: 1,322 Days
• Field of Search: 345/160, 345/133, 345/440, 345/134, 345/593, 345/708, 345/158, 345/426, 345/431, 345/432, 345/418-421, 708/105, 182/201
• US Class Current: 345/160
• CPC Class Codes: G06T 11/206 Drawing of charts or graphs

Abstract

A graphing calculator (10) or other computer based teaching tool that displays inequalities on a display screen. In contrast to prior art devices, the present invention provides displays of inequalities that are mathematically correct and consistent with non-electronic display of inequalities such as textbooks and black board representations to reinforce traditional teaching methods and help the student or user to readily see and understand the mathematical concepts involved. The display methods of the present invention are particularly useful for small, low-resolution displays that are typical of handheld computers and calculators.

Claims

1. A graphing calculator that provides graphing of inequalities comprising:

a display screen,

a cursor on the display screen,

a key panel having keys at least capable of selecting positions of said cursor on said display screen,

a processor for executing programming that instructs said processor to perform the following steps;

a) display an Y=Editor input screen on the display screen with one or more “

Y=”

prompts which allow a user to define one or more equations or inequalities,

b) display the graph of one or more equations or inequalities defined by the user where strict inequalities are shown as a dotted line with shading; and

c) allow the user to select between union and intersection shading.

2. The graphing calculator of claim 1, further comprising the step of graphing the union of the inequalities.

3. The graphing calculator of claim 2, wherein the union of the inequalities is graphed in a different style shading.

4. The graphing calculator of claim 1, further comprising the step of graphing the intersection of the inequalities.

5. The graphing calculator of claim 4, wherein the intersection of the inequalities is graphed in a different style shading.

6. A computer based mathematics teaching tool that provides an X=Editor comprising:

a screen capable of displaying at least straight lines in any direction and a cursor;

a key panel having keys at least capable of selecting positions of said cursor on said screen;

a processor for executing programming that instructs said processor to perform the following steps;

a) display an Y=Editor input screen on the display screen with one or more “

Y=”

prompts which allow a user to define one or more equations or inequalities,

b) display the graph of one or more equations or inequalities defined by the user where strict inequalities are shown as a dotted line with shading and

c) allow the user to select between union and intersection shading.

7. The computer based mathematics teaching tool of claim 6, further comprising the step of graphing the union of the inequalities.

8. The computer based mathematics teaching tool of claim 7, wherein the union of the inequalities is graphed in a different style shading.

9. The computer based mathematics teaching tool of claim 6, further comprising the step of graphing the intersection of the inequalities.

10. The computer based mathematics teaching tool of claim 9, wherein the intersection of the inequalities is graphed in a different style shading.

11. A software user interface for a graphing calculator having the following steps:

a) providing an input display to allow the user to define a plurality of equations, inequalities and vertical lines,

b) graph the defined equations, inequalities and vertical lines, where strict inequalities are shown as a dotted line with shading

c) allow the user to select between union and intersection graphs of the plurality of inequalities.

12. The user interface of claim 11, wherein said processor is further programmed to input equations, inequalities and lines using a Y=Editor and an X=Editor.

13. The user interface of claim 11, wherein the choice of the intersection display by the user results in graphing the intersection of the plurality of inequalities in a different shade style than the inequalities.

14. The user interface of claim 11, wherein the choice of the union display by the user results in graphing the union of the plurality of inequalities in a different shade style than the inequalities.