Plotting to find guesses, Plotting to find guesses -8 – HP 38g Graphing Calculator User Manual
Page 106
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The Root-
Finder at Work
You can watch the process of the root-finder calculating and
searching for a root. Immediately after pressing {{SOLVE}} to
start the root-finder, press any key except
|
on
|.
You will see
two intermediate guesses and, to the left, the sign of the
expression evaluated at each guess. For example:
- - . 2 1 9 3 3 0 5 5 5 7 4 5
3- -1.31111111149
You can watch as the root-finder either finds a sign reversal or
converges on a local minimum/maximum or does not
converge at all. If there is no convergence in process, you
might want to cancel the operation (press |ONj) and start
over with a different initial guess.
Plotting to Find Guesses
The Plot view and the Plot Setup work as they do for the
Function aplet. The main reason for plotting in the Solve aplet
is to help you find solutions for those equations that have
difficult-to-find or multiple solutions.
Example
Consider the equation of motion for an accelerating body,
at^
X = D,t + —,
where
x
is distance, is initial velocity,
t
is time, and
a
is
acceleration. This is actually
two
equations,
y = x
and
y = v j + { a e ) l 2 .
Since this equation is quadratic for f, there can be both a
positive and a negative solution. However, we are concerned
only with positive solutions, since only positive distance
makes sense.
4-8 Solve