The web page 208306.htm presents and describes a program, QUAD, that performs the "quadratic formula" for solving certain quadratic equations of the form
QUAD1, part 1 | QUAD1, part 2 |
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A comparison of part 1 of the QUAD1 program with the QUAD program given on the earlier 208306.htm page, should confirm that the main part of the program is unchanged from one version to the other. The extra lines in QUAD1 are used to format the output of the program so that it looks nicer. Also, notice that the QUAD1 program calls (makes reference to) the TOSTR program in order to achieve a nicer looking output. TOSTR must be available on the calculator. The listing for the TOSTR program, was given on the 208304.htm page.
Naturally, one could enter the programs into a calculator. However, the TI-83 file for QUAD1 in is available at quad1.83p and the TI-83 file for TOSTR at tostr.83p. Depending upon your browser, you should be able to save the file to your disk and then transfer it via TI-Graphlink, assuming you have the program and the required cable.
We conclude this page with few sample runs of the TI-83 version of the QUAD1 program. We will be solving the following quadratic equations:
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We open the PRGM menu by pressing the ![]() ![]() |
![]() | All that has been accomplished is to paste the command
prgmQUAD1 onto the screen. We will have to press the
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![]() | In Figure 3 the program has started.
The calculator has asked for, and we have supplied, values for the
coefficients A, B, and C.
We have entered the value 1 for A,
6 for B and the value 9 for C.
These are the coefficients for
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Figure 4 shows output from the calculator. It writes the word DISCRIMINANT
followed, on the next line, by
the value of the discriminant. Recall that the discriminant for
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![]() | The program was completed in Figure 4. To restart it, we press
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![]() | To accept our final value and continue the program we press
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In Figure 7 we have restarted the program by pressing the ![]() |
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Pressing the ![]() |
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In Figure 9 we have restarted the program by pressing the ![]() |
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Again, we press ![]() |
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In Figure 11 we have started the program again, this time to solve the problem
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![]() | The program finds the discriminant, finds that there are two answers, gives those values, and points out that the answers are RATIONAL ANSWERS. |
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In Figure 13 we have started the program again, this time to solve the problem
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We press the ![]() ![]() |
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In Figure 14 we found out that the value of the discriminant was 8.
Thus, from the quadratic formula,we know that the solutions are
(-B-sqrt(B2-4AC)) / (2A) (6-sqrt((-6)2-4*1*7)) / (2*1) (6-sqrt(36=28)) / 2 (6-sqrt(8)) / 2 |
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In Figure 16 we have started the program again, this time to solve the problem
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We leave Figure 16 by accepting the final value with the ![]() ![]() |
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In Figure 18 we se the program display of the exact answers, namely,
(-4-sqrt(7)) / 5 |
PRECALCULUS: College Algebra and Trigonometry
© 2000 Dennis Bila, James Egan, Roger Palay