HP 40gs HP 39gs_40gs_Mastering The Graphing Calculator_English_E_F2224-90010.p - Page 103

before, then we can change to the Solve aplet and enter into, change to

Page 103 highlights

Population type problems are also easily dealt with in this way. For example, "A population of mice numbers 5600 and is growing at a rate of 12.5% per month. How long will it be until it numbers more than one million?" Pressing CLEAR (above DEL) clears out the existing expressions, and we can enter the formula for the GP modeling the situation shown right. Because this is a non-recursive rule, the two initial values of 5600 and 6300 will be automatically calculated when you enter the rule into U1(N). All we need do now is switch to the Numeric view to find, with some experimenting, that U1(46) is the first to exceed one million. It is also possible to answer these questions in the Solve aplet. For example if we use the Sequence aplet to define U1(N)=2^(N-1) as before, then we can change to the Solve aplet and enter into E1 the equation U1(N)=10000, change to the NUM view and press and obtain an answer of 14 ⋅ 29 . This means, of course that N=15 is the first term exceeding 10000. The reason why we did not use E1(N)>10000 is that the Solve aplet is unable to deal with inequalities even though no error message is given if you try. 103

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Population type problems are also easily dealt with in this way.
For example, “A population of mice numbers 5600 and is growing at a rate of 12.5% per
month. How long will it be until it numbers more than one million?”
Pressing
CLEAR
(above
DEL
) clears out the existing expressions, and
we can enter the formula for the GP modeling the situation shown right.
Because this is a non-recursive rule, the two initial values of 5600 and
6300 will be automatically calculated when you enter the rule into
U1(N)
.
All we need do now is switch to the Numeric view to find, with some
experimenting, that
U1(46)
is the first to exceed one million.
It is also possible to answer these questions in the Solve aplet. For
example if we use the Sequence aplet to define
U1(N)=2^(N-1)
as
before, then we can change to the Solve aplet and enter into
E1
the
equation
U1(N)=10000
, change to the
NUM
view and press
and obtain an answer of
14 29
.
This means, of course that
N=15
is
the first term exceeding 10000.
The reason why we did not use
E1(N)>10000
is that the Solve aplet is unable to deal with inequalities even
though no error message is given if you try.
103