Lab 8 – Graphing Calculators I (TI-92)
1. Graph the equation y = 3x2 – 5x – 7:
a. Hit green rhombus, then “Y=”
b. If there are already equations entered, delete them. Use the cursor pad to highlight them then hit CLEAR.
c. Enter the equation for y1=
d. Hit the green rhombus, then GRAPH.
e. Hit the F2 button to play around with the scaling, so that it is in a nice viewing window.
2. Where are the zeroes of this function?
a. Use the cursor to move along the curve and find where it is close to 0.
b. Alternatively, hit F5 (math) and then 2 (zero). Then use the cursor to locate a lower bound, and hit ENTER. Do the same for the upper bound.
c. Find the minimum using the command under F5.
d. Play with some of the other commands under F5.
3. Now let’s try something different.
a. Set y1(x) to 2x-1. Set y2(x) to 2x+1. Then set y3(x)=y1(x)+y2(x). What do you notice? Change the coefficients and see how your answers change.
b. Return to y1(x) = 2x-1 and y2(x) = 2x+1. Then set y3(x)=y1(x)-y2(x). What do you notice? Change the coefficients and see how your answers change.
c. Return to y1(x) = 2x-1 and y2(x) = 2x+1. Then set y3(x)=y1(x)*y2(x). What do you notice? Change the coefficients and see how your answers change.
d. Finally, explore y1(x)/y2(x).
4. Zooming, etc.
a. Graph the function f(x)=1/x. Any interesting surprises? Zoom in and out. What do you notice?
b. Graph the function f(x)=5sin(1/x2). What do you notice? Zoom in closer to zero. Any surprises? Zoom in even more…
c. Enter the function f(x)=(x4-3x2+3x-9)/(x2-5x+3). Zoom out repeatedly. What do you notice?
5. Enter y1(x) = 5sin(x) and y2(x)=x2-7. Where do they intersect?
a. Method 1: Use the cursor key to approximate it.
b. Method 2: Use the Intersect command under F5.
c. Method 3:
- Hit the green rhombus, then TblSet. Set “Independent” to “AUTO”.
- Hit the green rhombus, then Table. Scroll down to find the intersection. Hit F2 to revise the starting point and increment in order to find better approximations of the zeroes.
6. More with Table. See if you can generate each of the following. You will need to adjust the functions in your “Y=” window, as well as the setup of the table.
a. Odd integers.
b. Square numbers.
c. The powers of 2
d. The arithmetic sequence with a=5 and d= – ˝
e. The geometric sequence with a = 5 and r = 3