Solving with a TI-92
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Solving with a TI-92
Leviathan writes:
> Hello, I hope you can help me.
> My Question:
> Is it possible, that the TI92 shows me the way of
> the solution.That means can the TI92 display
> step by step the calculation.
>
> For example:
> solve(y=2cos(3x+3,14),x)
> Problem/Question
>
> 2cos(3x+3,14)=0 |
>
> "way of solution" or "step by step"
>
> cos(3x+3,14)=0 | Subst.z=3x+3,14
>
> etc.
This is one of the things that the TI-92 is excellent for, especially in an
instructional situation.
BTW, it looks to me like the writer is not trying to solve the equation for x,
but rather to find the zeros. That's a different story, a bit. I am also going
to suppose that "3,14" here is intended as a representation of the number _pi_.
If you want to know the zeros of the function y = 2 cos(3x + pi) you could,
of course, graph this function or use a solver method (much as with the TI-8x
calculators). Because of the use of the deciamal approximation for pi in the
problem cited, perhaps this is what is desired. But if you want a _theoretical_
or _exact_ solution, then the TI-92 will provide you with one.
One method is to simply enter the equation, then proceed to solve it step by
step with algebraic/trigonometric operations, including inverses, much as you
would on paper. You should be sure that you are in Exact mode, and should use
the _symbol_ for pi when you mean this number.
The first step would be to divide the whole _equation_ by 2 (really we are
dividing both sides by 2 at the same time). Then take the inverse cosine, etc.
Eventually (after not too many steps) you will arrive at an expression of the
form g(y) = x.
In this case, because of the periodic nature of the cosine function, the TI-92
includes an undetermined integer multiple in the answer -- there are an
infinite number of zeros. Putting in a specific value for y (say 0) will give
you the set of corresponding values of x.
Now for the fun part! The TI-92 lets you save the lines you have just entered
as a _script_ (a small text file). You can export these, if you like, or you
can comment them right on the TI-92 and run back through them _live_,
re-executing all of the commands and re-demonstrating the solution right in
front of your audience's eyes (if you have a viewscreen connected).
Turn the shoe around now. It is possible to assign students the task of
_creating_ and _submitting_ a suitably commented script to perform a particular
solution! Warming up to this, one might hand out (by linking) a partially-
completed or not-fully-correct script and ask students to "fix it up" as an
assignment. Well, you can probably start seeing the possibilities.
Wouldn't that be a lot more fun that doing everything with pencil and paper?
Of course, it would take a TI-92 in every student's hands, and that won't
happen for a few years yet. I can't wait!
RWW Taylor
National Technical Institute for the Deaf
Rochester Institute of Technology
Rochester NY 14623
>>>> The plural of mongoose begins with p. <<<<