TI86 equation solving
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TI86 equation solving
JLC <nsx3000@BIGFOOT.COM> writes:
> How do I solve a quadratic equation in TI86? (ex. X^2+X-2=0)
Use the quadratic formula -- 99% of the time this will be the most satisfactory
method. And it's a good idea to enter it directly, too, to watch what is
happening. Something like this:
1 -> a : 1 -> b : -2 -> c
b*b-4a*c -> D
(-b + sqrt(D)) / (2a) -> x1
(-b - sqrt(D)) / (2a) -> x2 (recall the Entry to save re-typing)
Change to fractions, if you like.
Check:
x1^2 + x1 - 2
Do you get 0? Also check the other root (Entry again).
This should work just fine even for complex roots. Keep your eye on D
as you work to see how the nature of this number afffects the nature of
the roots. For example, if D is positive and a perfect square you would
predict the roots to be rational and the polynomial to be factorable
(if you had some reason to want it in factored form, you _could_ work it out).
There are, of course, other more general ways to solve equations
on the TI-86 (the solver, or graphing), but you would normally
save these high-power methods for tougher equations.
RWW Taylor
National Technical Institute for the Deaf
Rochester Institute of Technology
Rochester NY 14623
>>>> The plural of mongoose begins with p. <<<<
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