hp40g+.book Page 23 Friday, December 9, 2005 1:03 AM
Solution 1
Start by defining G(X):
DEF 
G
X 
= 2 
X 3 
X 
2
Now press 
:
Press 
and 
to select the numerator and denominator, and then
press 
. This leaves G(X) displayed:
Finally, apply the TABVAR function:
TABVAR
and press 
a number of times until
the variation table appears (shown above).
The first line of the variation table gives the sign of
g′(x) according to x, and the second line the variations of g (x). Note that for TABVAR the function is always called F.
We can deduce, then, that g(x) increases over [0, 2].
If you had been in
2 ⋅ X + 3 F =
X + 2
Press 
to get the result at the right.
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