Figure 1
|
We start by pressing the
key to obtain the menu of programs. Then we
use the key to move the highlight down to
the QUAD program, as shown in Figure 1.
|
Figure 2
| We press the key to leave Figure 1
and produce the bottom line of the screen on Figure 2. |
Figure 3
|
We press the key again to execute the QUAD
program. Figure 3 shows the immediate result. The program asks for a value for
the coefficient A.
Since we are looking at the problem
x2 + 6x + 8 = 0
we know that the leading coefficient is 1. We have responded by pressing the
key. This is the condition shown in Figure 3.
Then we press to have the calculator accept our answer.
This will move us to Figure 4.
|
Figure 4
| The calculator requests the value of B.
We respond with .
The calculator asks for the value fo C.
We press the key. This produces the image seen in Figure 4. |
Figure 5
| We leave Figure 4 by pressing the key.
The calculator processes the information given and produces the result seen
in Figure 5. In particular, we see that the value of the discriminant is 4,
that there are two answers, and that those values
are x=-2 and x=-4. |
Figure 6
| Next we want to run the program to solve
x2 + 6x + 9 = 0
We can run the program again by pressing the key.
Again the program requests the coeeficients, one at a time. We supply
those values to leave the screen as shown in Figure 6.
|
Figure 7
| We leave Figure 6 by pressing the key.
The calculator processes the information given and produces the result seen
in Figure 7. In particular, we see that the value of the discriminant is 0,
that there is one answers, and that answer is x=-3. |
Figure 8
| Next we want to run the program to solve
x2 + 6x + 10 = 0
We can run the program again by pressing the key.
Again the program requests the coeeficients, one at a time. We supply
those values to leave the screen as shown in Figure 8. |
Figure 9
| We leave Figure 8 by pressing the key.
The calculator processes the information given and produces the result seen
in Figure 9. In particular, we see that the value of the discriminant is -4,
and that there are no Real Number answers. |
Figure 10
| Next we want to run the program to solve
x2 + 6x + 7 = 0
We can run the program again by pressing the key.
Again the program requests the coeeficients, one at a time. We supply
those values to leave the screen as shown in Figure 10. |
Figure 11
| We leave Figure 10 by pressing the key.
The calculator processes the information given and produces the result seen
in Figure 11. In particular, we see that the value of the discriminant is 8,
that there are two answers, and that those values are
x=-1.585786438 and x=-4.414213562.
It is important to note that these are merely approximations to the
correct answers. We note that the discriminant is 8, which is not a perfect square.
Therefore, the answers will be irrational numbers. The calculator
has provided an approximation to those irrational numbers. That is
the best it can do given the programming that was done. |
Figure 12
| Finally, we want to run the program to solve
8x2 + 6x + 1 = 0
We can run the program again by pressing the key.
Again the program requests the coeeficients, one at a time. We supply
those values to leave the screen as shown in Figure 12. |
Figure 13
| We leave Figure 12 by pressing the key.
The calculator processes the information given and produces the result seen
in Figure 13. In particular, we see that the value of the discriminant is 4,
that there are two answers, and that those values are x=-1/4 and x=-1/2.
In this case the calculator was able to express the answers
exactly. |