# The Expert: Sequences & Series - HP 39gs Master Manual

Graphing calculator.

T
E
:
S
T
E
:
S
H
E
X
P
E
R
T
H
E
X
P
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R
T
Defining a generalized GP and the sum to n terms for it.
If we define our GP using memory variables then it
becomes far more flexible.
The advantage of this method is that you now need only
change the values of
A
change the sequence.
Defining a series (sum to n terms of a sequence) is fairly straight-forward
using a similar method. Note the reference to
.
U2
Once
is defined in this way you can change both
U2
simply storing new values into
Solving sequence problems
Questions like "What term is the first to be greater than 10 000?"
or "When does S
first exceed 10 000?" can be answered in the
n
Simply move into the
N
and type it in. The table jumps to that value.
For example, in answer to the first question, we might estimate
However we would find that
guesses, we find that T
15
problem is as easily solved in this way.
&
&
E
Q
U
E
N
C
E
S
E
Q
U
E
N
C
E
S
and
in the
view to
R
HOME
U1
and
from the
A
R
column, make a guess as to the term you require
is far too large. By successive
U1(35)
is the one we were seeking. The second
S
S
E
R
I
E
S
E
R
I
E
S
in the definition of
&
. by
U1
U2
view.
HOME
view.
NUM
.
N=35
102
15