**HOW TO USE THIS APPLET**

## The slider area

The sliders change the parameters m and b in the linear relation y = mx + b; the parameters m, x_{1} and y_{1} in the linear relation y - y_{1} = m( x - x_{1} ) and the parameters a, b and c in the the linear relation ax + by + c = 0.

- Drag a slider to change the value of a parameter.
- The left and right arrow keys can be used to change the selected parameter [light blue].
- The up and down arrow keys can be used to increase or decrease the selected parameter. (Use this feature for fine adjustments.)
- If the arrow keys don't respond, click the cursor in the applet frame then try again.
- Drag a parameter scale to "move" it. (ie. Change the range but maintain the scale "length".)
- Drag towards or away from a parameter thumb to "re-scale" the scale.
- Select the corresponding parameter button to enter a value for a parameter.

## The graph area [y = mx + b and y - y_{1} = m( x - x_{1})]

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

- Use the "RESET" button to restore the applet to the initial state.
- THE SHIFT KEY : Drag in the graph area to move the entire coordinate system.
- THE CONTROL KEY : Drag in the graph area towards or away from the origin to change the scale.

RETURN TO MAIN PAGE