How do They Differ?

Procedure:

	Turn your TI73 Graphing Calculator on.
	Press Y= and enter the following equations: Y1 = 1x Y2 = 2x Y3 = 3x Y4 = 4x
	Press Zoom and choose 4: Quadrant 1.
	Press TRACE. Be sure the top of the screen says y1=1x.

	The cursor will be on one graph.
	Use the cursor arrows to move left and right along the graphs.
	What do you notice about the x and y coordinates on the bottom of the screen?
	Move to the graph of Y2 by pressing the down arrow. Use the left cursor arrow to move the cursor so you can see it on the screen. What do you notice about the x and y coordinates on the bottom of the screen when you are on Y2?

Move to the graph of Y3 by pressing the down arrow. Use the left cursor arrow to move the cursor so you can see it on the screen. What do you notice about the x and y coordinates on the bottom of the screen when you are on Y3?

Move to the graph of Y4 by pressing the down arrow. Use the left cursor arrow to move the cursor so you can see it on the screen. What do you notice about the x and y coordinates on the bottom of the screen when you are on Y4?

	What does the number in front of the x in the equation do to the graph of the equation?
	If you wanted to make a steeper line what equation would you enter in the equation? Press Y= and replace equation y1 with a new equation that will be steeper than y4. Press Graph to see if you are right.
	If you want an equation that will fit between the graphs of y2 and y3 what would you write? Press Y= and replace the equation y1 with a new equation that will fit between y2 and y3.
	If you wanted to make a line that was less steep that y2 what would you write? Press Y= and replace the equation y1 with a new equation that will be less steep than y2.

Looking at Tables for Equations

Press TBLSET and be sure that the table set up is as illustrated:

Press TABLE and look at the values in the lists.

	What is in the first list?
	What do you notice about the values in the list Y1? How are they related to the corresponding values in the x column?

	What do you notice about the values in the list Y2? How are they related to the corresponding values in the x column?
	Use the cursor arrow to move to columns Y3 and Y4. What do you notice about the values in the list Y3? How are they related to the corresponding values in the x column?
	What do you notice about the values in the list Y4? How are they related to the corresponding values in the x column?
	Can you predict the value that would be associated with x = -1 for each list? Make a prediction and then move to the x column and move up one level by pressing the up cursor arrow. Use the right arrows to check your values for the four columns.
	Can you predict the value that would be associated with x = -5 for each list? Make a prediction and then move to the x column and move up until you reach x = -5. Use the right arrows to check your values for the four columns.

What happens when we add a number to given equation?

Press Y= and enter the following equations:

Y1 = 1x+2
Y2 = 2x+2
Y3 = 3x+2
Y4 = 4x+2

	Press GRAPH and describe what has happened to all four graphs.
	Trace along the graphs. First trace along Y1. What do you notice about the coordinates when you are on Y1?
	Move to Y2. What do you notice about the coordinates when you are on Y2?
	Move to Y3. What do you notice about the coordinates when you are on Y3?
	Move to Y4. What do you notice about the coordinates when you are on Y4?
	Do all four graphs pass through the same point on the y axis? What point is this? Why does this make sense?
	Can you make all the lines pass through the point (0,5)? Press Y= and change all the equations so they will pass through (0,5).