Sequence Definition and 1000 Threads

  1. barryj

    A puzzling math geometric sequence question.

    Homework Statement This problem is taken directly out of a textbook. "The first three terms of a geometric sequence are 1,2, and 4. Susanna said the 8th term of this sequence is 128. Paul said the 8th term is 29. Explain how the students found their answers. Why could these both be...
  2. anemone

    MHB Find the largest value in a sequence

    The sequence a_1,\;a_2,\;a_3,\cdots is defined by a_1=1, a_{2n}=a_n, a_{2n+1}=a_{2n}+1. Find the largest value in a_1,\;a_2,\;a_3,\cdots,\; a_{1989} and the number of times it occurs.
  3. Fernando Revilla

    MHB Cambree's question at Yahoo Answers (Convergence of a sequence)

    Here is the question: Here is a link to the question: Determine whether the sequence is divergent or convergent? - Yahoo! Answers I have posted a link there to this topic so the OP can find my response.
  4. E

    Product of a sequence identities

    HI, does anyone know a decent site where I can find a few product identities? I googled it, but all that came up were trig identities. I am not looking for those; I am specifically looking for product of a sequence identities: ∏
  5. B

    Alternative Proof of Cauchy Sequence ##\left(S_n\right) = \frac{1}{n}##

    I am looking for a different proof that ##(S_n) = \frac{1}{n}## is cauchy. The regular proof goes like this (concisely): ##\left|\frac{1}{n} - \frac{1}{m} \right| \leqslant \left|\frac{m}{nm}\right| \ (etc...) \ <\epsilon ## but I was thinking about an alternative proof. Is my proof...
  6. FeDeX_LaTeX

    Arithmetic Sequence Homework: Find the Sum

    Homework Statement This is taken from STEP I 1990, Q4. (i) The sequence a1, a2, ..., an, ... forms an arithmetic progression. Establish a formula, involving n, a1, and a2, for the sum of the first n terms. (ii) A sequence b1, b2, ..., bn, ... is called a double arithmetic progression if the...
  7. N

    Sequence question to do with tile patterns

    Homework Statement There are patterns made up of square tiles which I can not draw but only describe... Pattern 1 has 1 grey tile in centre and 8 dotted tiles around it Pattern 2 has 4 grey tiles in centre and 12 dotted tiles aound it Pattern 3 has 9 grey tiles in centre and 16 dotted...
  8. T

    Find the explicit formula for the nth term of the sequence?

    Homework Statement Consider the sequence n1, n2, n3, ... that satisfies the recurrence relation nk = nk-1 / k + 1 for all integers k ≥ 2 with the initial condition that n1 = 1. Find the explicit formula nk for the nth term of the sequence? 2. The attempt at a solution I calculated...
  9. A

    Shutdown sequence initialisation

    Hello, How to create a batch file that shuts down system at a particular time (not countdown but when the time approaches, it shuts down the system) after closing all the open programs? I don't want to use task scheduler P.S. how to make it a batch file that runs even when the system is...
  10. T

    Problem with function of sequence simple convergence

    Hello. I have a problem. I don't know how to finish my proof. Maybe someone of you will be able to help me. So task is: Suppose that fn and gn are function of the sequence. fn simply convergence(? don't know if english term is same) to f, and gn simply convergence to g. Need to prove that...
  11. B

    Convergence of Sequence ##(p_n)## to ##p##

    If ##p## is a limit point of ##E## then ##\exists \ (p_n) \ s.t. (p_n) \rightarrow p## For the sequence construction, can I just define ##(p_n)## as such: ##For \ q \in E, \ \ define \ (p_n) := \left\{\Large{\frac{d(p,q)}{n}} \right\}_{n=1}^\infty##
  12. W

    How Do I Adjust a Formula to Alternate Sequence Terms?

    Homework Statement I am trying to solve this problem and need help with one aspect.Homework Equations sequence: 0,-1,0,1 -- repeated.The Attempt at a Solution How do I make every 4th term of the sequence a negative number? for instance i have: (1 + (-1)^n)/2 but i don't know how to...
  13. W

    Prove the typewriter sequence does not converge pointwise.

    (Typewriter sequence) Consider the following sequence of functions on [0,1]. Let f1= X[0, 1\2], f2= X[1\2, 1], f3= X[0, 1\4], f4= X[1/4, 1\2], f5= X[1\2, 3/4], f6= X[3/4, 1], f7= X[0, 1\8], etc. Where X is the Characteristic function. (a) Prove that fn does not converge for any x in [0,1]...
  14. A

    MHB Prove No Uniformly Convergent Subsequence: Functional Sequence

    SOLVED Prove that the functional sequence has no uniformly convergent subsequence -check n \in \mathbb{R}, \ \ f_n \ : \ \mathbb{R} \rightarrow \mathbb{R}, \ \ f_n(x) =\cos nx We want to prove that {f_n} has no uniformly convergent subsequence. This is my attempt at proving that: Suppose...
  15. A

    MHB Sequence of continuous functions convergent to an increasing real function

    Hi. Could help me with the following problem? Let f be a real function, increasing on [0,1]. Does there exists a sequence of functions, continuous on [0,1], convergent pointwise to f? If so, how to prove it? I would really appreciate any help. Thank you.
  16. 5

    Next number in a sequence (definite integral problem)

    (definite integral problem) write as an expression Homework Statement \int0k 3x2 suggest an expression for definite integrals from x=0 to x=k Homework Equations see below The Attempt at a Solution when k= 0, \int0k 3x2 = 0 when k= 1, \int0k 3x2 = 1 when k= 2, \int0k 3x2 = 8...
  17. W

    Seq Convergence: Does a_n = (-1)^(n+1)/(2n-1) Converge or Diverge?

    Homework Statement Converge or diverge?Homework Equations \displaystyle a_{n} = \frac{(-1)^{n+1}}{2n-1}The Attempt at a Solution all i know is to perhaps take ln of numerator and denominator to get the exponent down below?
  18. A

    Sine function as an infinite sequence

    I have a vague understanding of how to derive the sine function from a Maclaurin Sequence however this isn't helping me figure out why: (1 - \frac{x^{2}}{4π^{2}}) (1 - \frac{x^{2}}{9π^{2}}) (1 - \frac{x^{2}}{16π^{2}})... = \frac{π^{2}}{x(x+π)}\frac{sin x - sin π}{x - π} Any help would be...
  19. B

    Convergence/Divergence and Monotonicity of a Sequence

    Homework Statement Show the following sequence to diverge, or converge. Determine if monotonic. a sub n=n+(1/n) The Attempt at a Solution I understand that the sequence does diverge. I found this because the limit as n→∞ the limit is going to ∞ as well. I found that the sequence is monotonic...
  20. S

    Finding the Limit of Sequence (1/n) with Detailed Criticism

    The general definition for the limit p of a sequence (pn) is \forall \epsilon > 0, \exists N \in \mathbb{N}:n \in \mathbb{N} \geq N \implies d(p_n,p) < \epsilon So, for the experience, I want to derive the limit of the sequence (1/n)_{n \in \mathbb{N}}. I would like detailed and harsh...
  21. A

    Proving sequence converges to 0

    Homework Statement Prove that the sequence a_n=\frac{1}{n}+\frac{(-1)^n}{n^2} converges to 0 using the definition of convergence. The Attempt at a Solution I'm pretty stumped on this one...all I've written is |\frac{1}{n}+\frac{(-1)^n}{n^2}-0| < \epsilon The only way I know how to...
  22. anemone

    MHB Find the 100th term of a given sequence.

    The increasing sequence 1, 3, 4, 9, 10, 12, 13 ... consists of all those positive integers which are powers of 3 or sum of distinct powers of 3. Find the 100th term of this sequence.
  23. H

    Proving Subspace Relation: lp and lq Sequences

    Homework Statement how to prove that the sequences space lp is subspace of lq for p smaller than q? Homework Equations The Attempt at a Solution I try to imply holder inequality but meanwile unsuccesfully
  24. D

    Is the Sequence {a_n} Convergent?

    Homework Statement Let {a_n} be a sequence | (a_n+1)^2 < (a_n)^2, 0 < (a_n+1) + (a_n). Show that the sequence is convergent Homework Equations n/a The Attempt at a Solution So I am feeling like monotone convergence theorem is the way to go there. It seems to me that (a_n+1)^2 <...
  25. S

    Need help on Direct Sequence Spread Spectrum

    Homework Statement I need to explain DSSS in my applied mathematics project (duration is three minutes of my talk). How do two users agree on which channel and the time to listen to so that they can exchange messages? Homework Equations Use Barker sequence as a channel encoder and...
  26. B

    Subsequential Limit of a Sequence

    I have a problem that asks for the subsequential limits, the limit superior, and the limit inferior for the sequence s_n = 4 ^{\frac {1} {n}} I haven't had trouble with my other problems, but I don't see any subsequences in the sequence (other than the sequence itself). Am I missing somthing?
  27. B

    Understanding Sup of Sequence: S_n

    Is my understanding of the concept of ##\underset{n}{Sup} \ S_n## correct? for instance, given the sequence: ##{S_n} = sin(\frac{n \pi}{2}). \frac{n+2}{2 n}## Then ##\underset{1}{Sup} \ S_n \ = \ \frac{3}{2}## ##\underset{10}{Sup} \ S_n \ = 0## ##\underset{k≥n}{Sup} \ S_n...
  28. I

    Limit of sequence lim n (1-cos(2/n))

    Homework Statement Homework Equations The Attempt at a Solution above picture ! Exam in 3 hours :( please help
  29. K

    I discovered a formula for the nth term of any sequence of numbers

    Hi there, I recently discovered a formula for the nth term that works for any finite sequence of numbers. I was just wondering whether a formula has already been discovered, and if not, how and where I should publish it. To give you an example of what i mean: one formula for the nth...
  30. Fernando Revilla

    MHB Clovis's question at Yahoo Answers (bounded sequence)

    Here is the question: Here is a link to the question: Real Analysis Sequences 10pts? - Yahoo! Answers I have posted a link there to this topic so the OP can find my response.
  31. I

    MHB How to prove sequence converges quadratically to a root of multiplicity

    A function f has a root of multiplicity $m>1$ at the point $ x_*$ if $f(x_*)=f'(x_*)=...=f^{(m-1)}(x_*)=0$. Assume that the iteration$ x_{k+1}=x_k-mf(x_k)/f'(x_k)$ converges to $x_*$. If$ f^{(m)}(x_*)≠0$, prove that this sequence converges quadratically.(We may use the Taylor's series, but I...
  32. J

    Estimating the error of an iterative sequence

    Homework Statement This isn't quite homework (though it's close), but I'm working on a quantum circuit and wish to implement an iterative method to find the square root of a number using elementary arithmetic operations (and without reciprocals). I've gotten most of it down, but the error...
  33. S

    Prove that sequence is monotonic

    Homework Statement Need to prove that the following sequence is monotonic ( decreasing ). \frac{1}{n^2}+\frac{(-1)^{n}}{3^n}Homework Equations - The Attempt at a Solution I have idea how to prove that the sequence is decreasing that is: a_{n+1} - a_{n} ≤ 0 but in this case, I can't get the...
  34. G

    Converting cDNA to Protein Sequence: Methods and Recommendations

    Has anyone here done this before? If so, kit recommendations and protocol? Any help would be awesome. Thanks!
  35. 3

    Sequence resulting from evenly dividing a line

    Hi, I'm new here and, as will become obvious from my question, neither a phycisist nor a mathematician. This is not a homework question, so I post it in this forum and hope that's okay. (I've aready asked on stack exchange but as far as I can see the answers given to me there were describing a...
  36. MarkFL

    MHB Aesity's question at Yahoo Answers regarding a geometric sequence

    Here is the question: Here is a link to the question: Geometric sequence question? - Yahoo! Answers I have posted a link there to this topic so the OP can find my response.
  37. G

    Convergent Sequence of Square Roots

    Homework Statement Let S_{1}=1 and S_{n+1}=\sqrt{2+S_n} Show that \left\{S_n\right\} converges and find its limit. Hint: First assume that the limit exists, then what is the possible value of the limit? Second, show that the sequence is increasing and bounded. Finally, follow the...
  38. I

    Limit of Sequence: Finding the Limit of a Sequence (2)

    Homework Statement Find the limit of this sequence An = \frac{n^{n}}{(n+3)^{n+1}} Homework EquationsThe Attempt at a Solution The answer is 0 but my answer is 1 thank you
  39. I

    Find the limit of sequence (trig term)

    Homework Statement find the limit of this sequence 1) An = \frac{\sqrt{n} sin (n! e^{n})}{n+1} 2) An = 4n^{3} sin\frac{1}{n^{3}} Homework Equations The Attempt at a Solution (1) |sin n! e^n)| ≤1 |An| ≤ \frac{ \sqrt{n} }{n+1} |An| ≤ \frac{ \sqrt{n}/n...
  40. O

    Show that sequence is unbounded

    Homework Statement Show that the sequence an= sqrt(n) is unbounded Homework Equations there is no relevant equation require. The Attempt at a Solution Actually, I'm a newbie for real analysis, I try to prove it by using contradiction method, but I stuck at half way, can anyone...
  41. Biosyn

    Sum of 5^1-5^2+5^3-5^4+...-5^{98}: e. (5/6)(1-5^98)

    Homework Statement Find the sum of 5^1-5^2+5^3-5^4+...-5^{98} a. (5/4)(1-5^99) b. (1/6)(1-5^99) c. (6/5)(1+5^98) d. (1-5^100) e. (5/6)(1-5^98) Homework Equations The Attempt at a Solution I feel as though this is actually a simple problem and that I'm not looking at it the right way. [5^1...
  42. B

    What is a Closed Form for the Sequence?

    Homework Statement Let Ʃ 1\(n^2-1) from n=2 to k. It says find a closed for it and prove it using sum notation. Homework Equations The Attempt at a Solution I can easily prove it by induction but I don't know what a closed form means. I tried looking it up online but there really...
  43. N

    Solve Mysterious Number Sequence Puzzle

    I am currently looking at a number sequence to solve a puzzle. I have identified the following with the sequence: 1. There are 3,684 digits in the series (3,684 being a Keith Number) 2. The sequence 789 appears 47 times in the overall sequence (47 is also a Keith Number) I'm thinking this...
  44. 0

    What is the lowest sum for K=2 in this infinite sequence with specific criteria?

    Homework Statement Say we have an infinite sequence of natural numbers A such that no K subsequences can be found adjacent such that the average of the elements in any subsequence is equal for all K subsequences. Sorry about my poor description, an example would be that {2, 3, 4, 1} wouldn't...
  45. Fernando Revilla

    MHB Proving the Limit of a Sequence with Toeplitz's Theorem

    I quote an unsolved problem posted on December 9th, 2012 in another forum Suppose \displaystyle\lim_{n \to \infty}a_n=a, \displaystyle\lim_{n \to \infty}b_n=b and without loss of generality that the sequences are (a_n)_{n\geq 0} and (b_n)_{n\geq 0}. We have to prove $L=\displaystyle\lim_{n\to...
  46. B

    Sequence of numbers divisible by 7.

    Homework Statement A sequence of 3-digit numbers divisible by 7 is given. Find: a) first three and last three numbers. b) how many numbers are there in that sequence. c) sum of all the numbers in the sequence. Homework Equations The Attempt at a Solution Cause they are 3...
  47. I

    Showing a Sequence Also Satisfies the Fibonacci Sequence

    Homework Statement The problem: Let r satisfy r2= r + 1. Show that the sequence an = Arn, where A is constant, satisfies the Fibonacci sequence an = an-1 + an-2 for n > 2. Homework Equations The given equations above are the only relevant equations. The Attempt at a Solution I...
  48. L

    MHB Help with Monotonic Sequence Convergence

    Could anyone help me out with the monoticity of this sequence please? \frac{2\ln(n)}{\sqrt{n+1}} . It should decline. I am investigating the convergence of one series and I need it to do the Leibniz test.
  49. C

    Probabilistic Sequence Function

    Let's assume we have a coin. When it is tossed, in first 2 times it comes head, and the next time tails. It goes like that in sequence, let's say two times. 2 head, 1 tails, 2 head 1 tails.. Btw, the coin is not fake, so head and tails both have equal probability of %50. Is there a function...
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