Sharp EL9900C EL-9900C - Page 62

Chapter 4: Basic Graphing Features - Basic Keyboard Graph Basics The graph examples in this exercise are called X-Y graphs. An X-Y graph is quite useful for clearly displaying the relationship between two variables. 7. Let's take a look at the graph. The vertical axis represents the Y value, while X is represented by the horizontal axis. It appears that the two diagonal lines cross at the point where the X value is somewhere between 2 and 3, indicating that Orange Cab costs less than the other, after 3 miles of traveling. 8. Next, press T to find the values per graph increment. When the traveling distance is 2 miles, the Tomato Cab charges 30 cents less overall than the Orange Cab, but it costs 30 cents more at 3 miles. To make the X increment smaller, press @ y. 9. When the Table setting window appears, move the cursor down to "TBLStep", type . 5, and press E. Now the Y values will be sampled at every 0.5 mile. 10. Press T to show the table again. It indicates that when the X value is 2.5, both Y1 and Y2 values are 6.5. It is now clear that if you are traveling 2.5 miles or more, the Orange Cab costs less. 2. Explanations of Various Graphing Keys Y: Displays the Graph Equation window. Up to 10 different equations can be entered. After the graph expression is entered, press E to store the equation. 52