# Linear Function Graph

## How to Use this Applet

### Definitions • <SHIFT>+drag: Hold down the <SHIFT> key, then drag the described object.
• <CTRL>+drag: Hold down the <CTRL> key, then drag the described object.
• <CTRL>+<SHIFT>+drag: Hold down both the <CTRL> key and the <SHIFT> key, then drag the described object.

### The Slider Area

The sliders change the parameters m and b in the linear relation y = mx + b; the parameters m, x1 and y1 in the linear relation y − y1 = m( x − x1 ) and the parameters a, b and c in the the linear relation ax + by + c = 0.

• Drag the slider thumb to change the value of a parameter. Use the <UP> and <DOWN> arrow keys to increase or decrease the selected parameter. (Use the keys for fine adjustments.)
• NOTE: If a key doesn't respond:
• position the cursor in the applet frame
• click the mouse button
• try the key again.
• Use the <LEFT> and <RIGHT> arrow keys to change the selected parameter. The selected parameter will have light blue slider gutters.
• Drag a slider scale to change the range of the scale while maintaining the scale length.
• Drag a location in a slider gutter towards or away from the thumb to change both the range of the scale and the scale length.
• Select the corresponding parameter button to enter a value for a parameter.

### The Graph Area (General Functions)

• <SHIFT>+drag in the graph area to move the entire coordinate system.
• <CTRL>+drag in the graph area, towards or away from the origin, to change the x and y axis scale.

### The Graph Area [y = mx + b and y − y1 = m( x − x1)]

• Drag the "dot" to move the line.
• Drag a location along the line other than the "dot" to change the slope of the line.

### The Graph Area [ax + by + c = 0]

• In ax + by + c = 0 form, the line can only be adjusted by changing the parameters.

### Other

• Select the MOVE ORIGIN button, then drag in the graph area to move the entire coordinate system.
• Select the CHANGE SCALES button, then drag in the graph area (towards or away from the origin) to expand or compress the scales on each axis.
• Select the PRECISION button to set number rounding.
• Select the TRACE x→y button to predict a y-value from a given x-value, based on the horizontal position of the cursor.
• Select the TRACE x←y button to predict an x-value from a given y-value, based on the vertical position of the cursor.
• Select the TRACE x↔y button to predict both a y-value from a given x-value, based on the horizontal position of the cursor, and to predict an x-value from a given y-value, based on the vertical position of the cursor.
• Select the RESET button to restore the applet to the initial state.