p.86 - 3 (1, .5, 3, .25, 5, .17, ...); (1, 2, .33, 4, .2, 6, ...)
[more decimal places will be needed]
8a lim (4 + 2/n + 1/(n^2)); by lilmit of sums, limit is 4
12d We are looking at (8/9)^n; the ratio of adjacent terms is manifestly
8/9 LT 1, hence the llimit is 0.
p.93 - 1 Note first that for 1 LT x_n LT 2, 1 LT x_(n+1) LT 2; this shows
bounded. Monotone can be demonstrated by showing that
x_n - (2 - 1/x_n) is positive, hence x_(n+1) is less than x_n
The limit is found by setting x_(n+1) = x_n and solving. (lim = 1)
7 By definiton of sup, there exists a member of A in every V_(1/n)(u)
subscript those eements as x_n corresponding to the 1/n neighborhoods.
Note that it may be necessary to use some elements of A more than once
(e.g., if A is the set of all negative integers)
p.99 - 6d Convergence can be established by appropriately altering the arguments
on pp. 92, 93. Then by noting that the subsequence obtained by
taking the square root for even values of n converges to e, we can
show that the sequence converges to e^2
8 Since x_n GEQ 0, The subsequence for odd n converges to a limit LEQ 0,
The subsequence for even n converges to a limit GEQ 0 [The
subsequences converge because all subsequences of a sequence converge
to the limit of the sequence] Since the subsequences converge to the
same limit, that limit must be 0, and x_n will converge to it.
10 Let's start with the interval [-1, 1]. I shall use the positive half,
hence start with 1/2, then to be in side 1/2, x_2 =1/4, then to be in
side 1/4, x_3 =1/6, then to be inside 1/8, x_4=1/10, etc.
Russell Campbell
Sun Sep 28 1997