1. Prove that if {xn} is a sequence that satisfies 2n² + 3 Xnl73 +5n2 +...
Suppose that a sequence {Zn} satisfies Izn+1-Znl < 2-n for all n e N. Prove that {z.) is Cauchy. Is this result true under the condition Irn +1-Fml < rt Let xi = 1 and xn +1 = (Zn + 1)/3 for all n e N. Find the first five terms in this sequence. Use induction to show that rn > 1/2 for all n and find the limit N. Prove that this sequence is non-increasing, convergent,
1 2 3 n-9n2 1. Consider an = 1+ 2n - 5n2 (a) (3 points) Does the sequence {an} converge or diverge? Show your work. (b) (3 points) Does the series an converge or diverge? Why? 2. (8 points) Use a comparison test to state whether the given series converges or diverges. 3. (6 points) Does the given series converge or diverge? If it converges, what is its sum? § (cos(n) – cos(n + 1))
- a) Let Xn be a sequence such that Xn+1 – xn| son for all n E N. Show that the sequence is Cauchy (and hence convergent). b) Is the result in part a) true if we assume that In+1 – 2n| <
2. Exercise 2. Consider the sequence (xn)n≥1 defined by xn = Xn k=1 cos(k) k + n2 = cos(1) 1 + n2 + cos(2) 2 + n2 + · · · + cos(n) n + n2 . (a) Use the triangle inequality to prove that |xn| ≤ n 1 + n2 for all n ≥ 1. (b) Use (a) and the -definition of limit to show that limn→∞ xn = 0. Exercise 2. Consider the sequence (In)n> defined by cos(k)...
(15 points) Suppose that a sequence {{n}.00, of real numbers satisfies 52n+1 = 3xn + 2 for all n E N. Show that {{n}", converges. What is limnto Xn? Explain why? the following four nrohlems
1. Let Xn ER be a sequence of real numbers. (a) Prove that if Xn is an increasing sequence bounded above, that is, if for all n, xn < Xn+1 and there exists M E R such that for all n E N, Xn < M, then limny Xn = sup{Xnin EN}. (b) Prove that if Xn is a decreasing sequence bounded below, that is, if for all n, Xn+1 < xn and there exists M ER such that for...
Prove that if Xn is a sequence of random variables that converge to a limit X almost surely, then Xn converges to X in probability. Give an example to show that convergence in probability does not imply almost sure convergence. Suppose X bar is the mean of random sample of size 100 from a large population with mean 70 and standard deviation 20. Without use CLT , give the estimated probability P(65<x<75).
3. Suppose X is a metric space with a sequence of points Xn e X with the property that for each n + m we have d(Xn, Xm) = 1. Prove that no subsequence of xn converges, and that therefore X is not compact. Hint: You could use the previous problem.
4. (20 pts) Let {xn} be a Cauchy sequence. Show that a) (5 pts) {xn} is bounded. Hint: See Lecture 4 notes b) (5 pts) {Jxn} is a Cauchy sequence. Hint: Use the following inequality ||x| - |y|| < |x - y|, for all x, y E R. _ subsequence of {xn} and xn c) (5 pts) If {xnk} is a See Lecture 4 notes. as k - oo, then xn OO as n»oo. Hint: > d) (5 pts) If...
Problem 2 Show that if the sequence of numbers (an)n-1 satisfies Inlan) < oo, then the series In ancos(nx) converges uniformly on [0, 27). This means, the partial sums Sn(x) = ) ancos(nx) define a sequence of functions {sn} = that converges uniformly on [0, 271]. Hint: First show that the sequence is Cauchy with respect to || · ||00.