Beginning Graphing Hints for TI's

I am using a TI-83.  There is little difference between the TI-83plus, TI-83, and the TI-82 for graphing. For shading with the TI-82, use the SHADE function.

Page 7 gives instructions for graphing lines.   Additional instructions are in Appendix B.

Example 1
Try graphing the equation y = (1/2)x, y = x, y = 4x on the same screen.

Press GRAPH after entering equations.

Notice how each graph is steeping than the previous one.  This is the slope of the line.  Experiment with different slopes. i.e.  y = -2x, y = -(1/2)x

y = mx where m is the slope of the line

83yequals.jpg (12288 bytes)Press the  Y =  key (noted by a red dot)
wpe4.jpg (5125 bytes)

Notice the = signs are highlighted.  Highlighting the = signs turns the equations on which allows you to see their graphs when GRAPH is pressed.

wpe2.jpg (5671 bytes)I pressed TRACE after pressing GRAPH.  Use the arrow keys to move left and right along Y1 (equation 1) .  Use the arrows keys (up and down) to scroll between each equation.

If you don't see the expression in the upper left-hand corner, press 2nd FORMAT, (above ZOOM key) and make sure everything is highlighted on the left hand side.
If you don't see the coordinates (x =, y = ) following above instructions.

Let's look at the y-intercept            y = mx + b where m = slope and b = y-intercept
Graph the equations y = x and y = x +5

wpe159.jpg (4687 bytes)
Notice the y-intercept for Y1 is (0,0)

wpe157.jpg (4793 bytes)
Notice the y-intercept for Y2 is (0,5)

You may need to clear old equations by moving the cursor to the desired line in the "Y =" screen and press CLEAR.

Remember to press TRACE to see equations and coordinates.

Shading isn't difficult and can help you tremendously in chapter 1

wpe7.jpg (4686 bytes)
Notice the triangle to the left of Y1.

wpe1.jpg (5959 bytes)
y   -x + 2

Place your cursor to the left of Y1 and press ENTER .  There are 7 different lime modes available.  Try them all!!

Here is the key to shading with the TI-83
  1. Solve for y
  2. Use the lower-left triangle for   (less than or equal to) i.e. example above
  3. Use upper-right triangle of   ( greater than or equal to)