1. Press the MODE key. Choose the Sequence option on the fourth line:
Func
Par
Pol
Seq
Everything else should be set to the left-most option.
2. Press the Y= key. To define a sequence, you must specify where you will start counting the numbers in the sequence (usually 1), how the n-th number in the sequence is determined, and the first number or numbers in the sequence.
Enter the following:
nMin = 1
u(n) = n + 1
(use the X, T, q, n key)
u(nMin) = {1}
3. To see the numbers in your sequence, you can make a table. Press TBLSET (2nd and WINDOW). Enter the following:
TblStart = 1
DTbl = 1
Now press TABLE (2nd and GRAPH).
4. One of the most useful things about sequences is that they can be defined recursively ... the next number in the sequence can depend on the number or numbers that came before it. Press Y= and enter the following:
u(n) = u(n-1) + u(n-2)
u(nMin) = {1, 1}
You can get the u by pressing 2nd and 7. The u(n-1) is the number in the sequence before the number u(n), that we are defining. The u(n-2) is the number in the sequence before u(n-1). Press TABLE. You should know this sequence!
5. You can graph a sequence much the same way you graph any other function. Press FORMAT (2nd and ZOOM). Choose the Time option on the first line:
Time
Web
uv
vw
uw
Press WINDOW and enter the following:
nMin = 1
Xmin = 0
Ymin = 0
nMax = 10
Xmax = 10
Ymax = 60
PlotStart = 1
Xscl = 1
Yscl = 10
PlotStep = 1
Press GRAPH. Press TRACE. Use the arrow keys to jump from point to point.