Sequence Definition and 1000 Threads

  1. gkamal

    Evaluate the limit of the sequence

    Homework Statement [/B]Homework Equations delta(x) = [b-a]/n xi=a+delta(x)i The Attempt at a Solution So, it is said that i have to use riemann sums to solve this one. what i did is i took the 1/12k out thus getting 1/12k[1/[1+1/12k] + 1/[1+2/12k] + 1/{1+19k/12k]] I found that xi =...
  2. C

    5-bit synchronous sequence recognizer design

    Homework Statement I am trying to design a 5-bit sequence recognizer. The circuit has to detect two sequences of bits. The first sequence is 11001. The second is 10010. The output when no sequence should be 00. When the 1st input sequence is detected, the output should be 01. When the second...
  3. karush

    MHB What is the Formula for the Sequence 242.9.1.24-26?

    $\text{write the formula for the sequence}$ $\text{.24 }$ $$a_n=\frac{n^{n+1}}{5^{n+1}}$$ $\text{.25 }$ $$a_n=\frac{(-1)^{n}+1}{2}$$ $\text{26.}?$
  4. K

    Help me understand zero sequence currents

    Hey, I have some questions regarding zero sequence current flow in a multi phase system I was hoping some kind soul could help me with. Imagine the following scenario illustrated in my bad paint drawing below: A delta-wye(n) transformer are supplying a non linear load producing 3rd harmonics...
  5. B

    B Why is the %change of the %change of a sequence so chaotic?

    Take the sequence 1,2,3,4,5,6,7,8,9,10... If you found the percent change for each interval and kept on finding the percent change of the percent change of the sequence, why does the change become more and more chaotic? Here is a quick table I made...
  6. karush

    MHB -z78 first four terms of the sequence of 𝑎_(𝑛+1)=𝑎_𝑛+𝑛,𝑎_1=−1.

    Write out the first four terms of the sequence defined by the recursion n_(n+1)=n_1+1,n_1=−1 $\text{Write out the first four terms of the sequence defined by the recursion}$ $$\displaystyle a_{n+1}=a_1+1,a_1=−1$$. $\text{so then}$ $$\displaystyle a_{0+1}=-1+0=-1$$ $\text{stuck!}$
  7. VMP

    I Problem with recursive sequence, sum and divisibility

    Hello everyone, I have an issue solving the following problem: You're on a mathematical Olympiad, there are m medals and it lasts for n days. First day committee gives U_{1}=1+\frac{1}{7}(m-1) medals. On the second day U_{2}=2+\frac{1}{7}(m-2-U_{1}) medals, and so on... On the last day...
  8. NihalRi

    Find common term for this sequence

    Homework Statement 6 /(12 + 1), 1/(22 + 1),6/(32 + 1),1/(42 + 1) Homework Equations none The Attempt at a Solution I suspect this is not that hard, I get the denominators but the numerator alternates so I though I would need 6 to be the base of a power that alternates between 0 and 1 but I...
  9. H

    I Proof of convergence & divergence of increasing sequence

    I'm using the book of Jerome Keisler: Elementary calculus an infinitesimal approach. I have trouble understanding the proof of the following theorem. I'm not sure what it means. Theorem: "An increasing sequence <Sn> either converges or diverges to infinity." Proof: Let T be the set of all real...
  10. alexmahone

    MHB Use the formal definition to prove that the following sequence diverges

    $\displaystyle s_n=\left(\frac1n-1\right)^n$ My attempt: For large $n$, the sequence oscillates between $e^{-1}$ and $-e^{-1}$ and therefore diverges. Now for the proof. Assume, for the sake of argument, that the sequence converges to $L$. $\exists N\in\mathbb{N}$ such that $|s_n-L|<0.1$...
  11. J

    B Explaining the Color Variations of Main Sequence Stars

    If all main sequence stars are engaged only in hydrogen fusion, why don't they all exhibit the same color?
  12. KT KIM

    I Completeness Property (and Monotone Sequence)

    I am studying Classical Analysis with Marsden book. At very first chapter it covers sequence, field, etc... The book has theorems 1."Let F be an ordered field. We say that the monotone sequence property if every monotone increasing sequence bounded above converges." 2."An ordered field is said...
  13. A

    I Concrete Examples of Exact Sequences in Linear Algebra

    I am trying to up my understanding on Manifolds, Tensors and Forms by reading a book of that title by Paul Renteln. I have got stuck fairly early on by his use of "exact sequences". Can some one give me a concrete example of a shot exact sequence of the form 0 -> U->V->W->0 where U,V,W are...
  14. K

    MHB Test for Cauchy sequence (with limsup and log)

    If $\{x_n\}_{n \ge 1}$ is real sequence and $\limsup\limits_{n \to \infty} \frac{1}{n} \log |x_{n+1}-x_n|<0$, prove that $\{x_n\}$ is Cauchy sequence. My work: Let $a=\limsup\limits_{n \to \infty} \frac{1}{n} \log |x_{n+1}-x_n| <0$. Then, for every $\varepsilon >0$ there exist $N \in...
  15. W

    Define the notation used here in describing a series?

    Homework Statement "For the given series, write formulas for the sequences an , Sn, Rn and find the limit as n->∞ (if it exists) Homework Equations ∑∞1 ((1/n) - 1/(n+1) The Attempt at a Solution I know how to take the limit, that's no problem. I'm a bit confused about what an , Sn, Rn are...
  16. P

    MHB Understanding Complex Geometric Sequences: A Revision Question

    need a hand with a revision question, I don't quite understand how to go about solving it question is attached below
  17. A

    Positive Sequence Resistance and Reactance calculation

    Hi, I have following two parameters with me a) Maximum three phase fault current in amperes (A) and phase angle in degrees (B). I want to calculate the positive sequence resistance (R) and reactance (X) from above two variables for a symmetric system. I couldn't figure out a way to find R and...
  18. M

    A Hodge Dual as Sequence of Grade Reducing Steps

    If we seek a bijection $$\wedge^p V \to \wedge^{n-p} V$$ for some inner product space ##V##, we might think of starting with the unit ##n##-vector and removing dimensions associated with the original vector in ##\wedge^p V ##. Might this be expressed as a sequence of steps by some binary...
  19. M

    B Definition of the limit of a sequence

    The definition of a limit of a sequence, if the limit is finite, is: lim n >infinity un (un is a sequence) = l <=> ∀ε> 0, ∃N: n > N => |un - l| < ε This just means that un for n > N has to be a number for which: l -ε < un < l + ε Now, I'm wondering, can't we just say: n > N => |un -l| <...
  20. R

    [Linear Algebra] Closed formula for recursive sequence

    Homework Statement Homework Equations a) the one given b) det(A-λI) = 0 find λ values using A c)use λ values to find eigenvectors The Attempt at a Solution This wasn't explained well enough so I can understand it in class. So far, I made the matrix being multiplied to A have the following...
  21. Mr Davis 97

    B Indexing Sequences: Do We Start at 0 or 1?

    Say we have a periodic sequencs, ABCDABCDABCDA... etc. We would normally call A term 1, B term 2, C term 3, etc. However, to find the nth term, do we need to designate A as term 0, B as term 1, etc? Since we would use n mod 4 to find the nth term, wouldn't this mean that 4, 8, 12, etc would have...
  22. T

    MHB Determining the convergence or divergence of a sequence using comparison test

    I have this series: $$\sum_{k = 1}^{\infty} {4}^{\frac{1}{k}}$$ To solve this, I am trying to compare it to this series $$\sum_{k = 1}^{\infty} {4}^{k}$$ So, I can let $a_k = {4}^{\frac{1}{k}} $ and $b_k = {4}^{k}$ These seem to be both positive series and $ 0 \le a_k \le b_k$ Therefore...
  23. T

    MHB Determining the convergence or divergence of a sequence using direct comparison

    I have $$\sum_{n = 2}^{\infty} \frac{{(\ln\left({n}\right)})^{12}}{n^{\frac{9}{8}}}$$ We can compare it to $ \frac{1}{{n}^{\frac{1}{8}}}$. $ \sum_{n = 1}^{\infty} \frac{1}{{n}^{\frac{1}{8}}}$ diverges because $p < 1$ in this case. So, if I can prove that $...
  24. karush

    MHB Convergence of Sequence with Increasing Values of n?

    ok I noticed that n \ge 0 so we have all positive numbers and with increasing values of n this will go converge to zero I can only show this by looking at a graph of the the expression. apparently the expression would have to rewritten to take the limit?
  25. T

    MHB Why Is the Limit of This $\ln$ Sequence Incorrect?

    If I have this sequence $$a_n = \ln\left({\frac{n}{n^2 + 1}}\right)$$ I need to find: $$ \lim_{{n}\to{\infty}} \ln\left({\frac{n}{n^2 + 1}}\right)$$ Shouldn't I be able to find the limit of$$ \lim_{{n}\to{\infty}} \frac{n}{n^2 + 1}$$ (which is $0$) and then substitute the result of that...
  26. T

    MHB Limit of Natural Log Sequence: How to Find It Using L'Hopital's Rule?

    I have this sequence: $${a}_{n} = \ln \left(\frac{12n + 2}{-9 + 4n}\right)$$ I need to find the limit of this sequence. How can I go about this? Do I need to apply L'Hopitals rule? I'm unsure how to simplify this expression. If I use the rule $\ln(\frac{a}{b}) = \ln a - \ln b$ I get $\infty -...
  27. cnh1995

    Rotor and negative sequence impedance of alternator

    When an alternator is supplied with a 3-phase voltage and its rotor is rotated in opposite direction to that of the stator rmf, the ratio phase voltage/phase current is the negative sequence impedance of the alternator. My understanding of this is as follows: When rotor is rotated in opposite...
  28. J

    A Convergence of a cosine sequence in Banach space

    Does the sequence \{f_n\}=\{\cos{(2nt)}\} converge or diverge in Banach space C(-1,1) endowed with the sup-norm ||f||_{\infty} = \text{sup}_{t\in (-1,1)}|f(t)| ? At first glance my intuition is that this sequence should diverge because cosine is a period function. But how to really prove...
  29. A

    What is a positive sequence model of an induction machine?

    I'm trying to understand a 3 phase induction machine model used as a generator in a Doubly Fed Induction Generator (DFIG) arrangement in Simulink. In this model for the induction generator component, they have stated that the model is a "Positive sequence model" of the induction generator...
  30. A

    Math Bachelor's, Masters and Phd's sequence for Math & Physics

    Hello, It seems like mostly, the masters degree is skipped for those who are seeking a Phd degree (from Bachelor's to Phd directly). I'm in my fourth year as undergraduate, studying physics. I like both math and physics and I really want to master them both. The thing is that my university...
  31. D

    How to Calculate Net Resistance in an Infinite Sequence of Resistors?

    Homework Statement From the picture below, calculate the net resistance between points A and B if ##R_1=12## ##R_2=3.75## Homework Equations 3. The Attempt at a Solution [/B] I cannot think of any way but to find the equivalent resistance od ##R_1## and ##R_2## and add them up but since there...
  32. adjacent

    Arithmetic sequence involving years

    Homework Statement A 25 year old programme for building new houses began in Core Town in the year 1986 and finished in 2010. The number of houses built each year form an arithmetic sequence. Given that 238 houses were built in 2000 and 108 in 2010, find the number of houses built in 1986...
  33. M

    MHB Each exact sequence can be arised by short exact sequences

    Hey! :o Let $R$ be a commutative ring with unit. We have that if the sequences $0\rightarrow A\rightarrow B\overset{f}{\rightarrow}C\rightarrow 0$ and $0\rightarrow C\overset{g}{\rightarrow}D\rightarrow E\rightarrow 0$ are exact, then the sequence $0\rightarrow B\overset{gf}{\rightarrow}...
  34. cnh1995

    Negative sequence currents in an alternator

    We recently performed one experiment regarding measurement of negative sequence impedance of an alternator(unloaded) in our lab session. The alternator was star connected and we shorted Y and B phases together, leaving R phase open(an L-L fault). How does this arrangement generate negative...
  35. karush

    MHB Find the 18th term in the sequence:

    Find the $18th$ term in the sequence: $$\frac{1}{2},1,2 $$ $$a_1= \frac{1}{2}\ \ \ \ n=18\ \ \ \ r=2 $$ $$a_n=a_1\cdot r^{n-1}=131072$$
  36. L

    Recursive sequence problem, or something similar

    Homework Statement define calculation for the numbers ( a ; b; c) such that the new triplet is as follows. (a ; b ; c) --> transforms into --> (b+c ; c+a ; a+b) the first terms for a,b,c are : (1 ; 3 ; 5) Perform the calculation 2015 times, such that the new resulting numbers of the triplet...
  37. Z

    Hashing: Quadratic Probing sequence

    Homework Statement Hi, I want to generate probing sequence using quadratinc probing technique. If j =4 & table size = 19 & assuming h(K) = 9. Homework Equations h(K), h(K) + 1, h(k) -1, h(k) + 4, h(K) - 4, ... h(K) + (TSIZE -1)power 2 / 4, h(k) - (TSIZE -1) power 2 /4 all divided modulo TSize...
  38. Jess Karakov

    Sequence Convergence/Divergence Question

    Homework Statement Determine which of the sequences converge or diverge. Find the limit of the convergent sequences. 1) {asubn}= [((n^2) + (-1)^n)] / [(4n^2)] Homework Equations [/B] a1=first term, a2=second term...an= nth term The Attempt at a Solution a) So I found the first couple of...
  39. karush

    MHB Find the 79th term in the sequence

    Find the 79th term in the sequence - 7, - 4, - 1 $$a_n=a_1+\left(a_n-1 \right)d$$ $$n=79,\ \ a_1=-7, \ \ d=-3$$ $$a_{79}=-7+\left(79-1\right)\left(3\right)=227$$ I just followed an example?
  40. A

    A limit involving a recurrent sequence: a(n+1)=a(n)*(a(n)+4)

    Homework Statement Let (an)n≥1 be a sequence with a1≥0 and an+1=an(an+4), n≥1. Compute limn→∞ (an)(1/(2n)). Homework Equations a1≥0 an+1=an(an+4), n≥1 L = limn→∞ (an)(1/(2n)) The Attempt at a Solution Firstly, I had tried to see if an can be expressed only in terms of a1, but I couldn't get...
  41. Albert1

    MHB How Can You Solve for $a_n$ in the Sequence Given $2S_n = a_n + \frac{1}{a_n}$?

    A sequence {$a_n$},$S_n=a_1+a_2+-----+a_n$,for each $n\in N, a_n>0$ if $2S_n=a_n+\dfrac {1}{a_n}$ please find $a_n=?$ (express in $n$)
  42. P

    MHB Arithmetic and geometric sequence

    *I am struggling with arithmetic and geometric sequences. if the 4th term is m-8, 6th term 8m+3 and 8th term is 10m-5 Calculate the 1st and 5th term Which term will have a value of -70The 4th term of geometric sequence is -16 and the 6th term is -64. Calculate the 3rd and 5th terms. thank you...
  43. P

    Is the Limit of an Irrational Sequence Also Irrational?

    Hello! So let's say that you have a sequence ##a{_n}## and the limit as ##n->{\infty}## gives the finite number ##b## not equal to zero. If ##a{_n}## is known to be irrational, and ##a{_n}{_+}{_1}## can be shown to be irrational, does it follow by induction that ##b## is irrational? Is there any...
  44. M

    Intuitive explanation of lim sup of sequence of sets

    Hi, I can derive a few properties of the limit inferior and limit superior of a sequence of sets but I have trouble in understanding what they actually mean. However, my understand of lim inf and lim sup of a sequence isn't all that bad. Is there a way to understand them intuitively (something...
  45. iheadset

    B Markov model on a sequence of numbers

    Dear Sir, Assuming that my lottery machine can generate 10 numbers (0..9), in which 0 and 9 are supposed to be starting and ending states of my Markov chain. I apply Markov chain to model each number appearance because I would want to modify the random generation process into, say, my own...
  46. G

    The Limit of a Matrix Sequence as n Approaches Infinity

    Homework Statement [/B] Find the limit as ##n \to \infty ## of ##U_n(a) =\begin{pmatrix} 1 & 0 & 0 \\ 0 & 1 & a/n \\ 0 & -a/n & 1 \end{pmatrix}^n##, for any real ##a##. Homework EquationsThe Attempt at a Solution I find ##U =\begin{pmatrix} 1 & 0 & 0 \\ 0 & \cos a & \sin a \\ 0 & -\sin a &...
  47. Euler2718

    Bounded Monotonic Sequence Theorem

    Homework Statement [/B] Use the Bounded Monotonic Sequence Theorem to prove that the sequence: \{a_{i} \} = \Big\{ i - \sqrt{i^{2}+1} \Big\} Is convergent.Homework EquationsThe Attempt at a Solution [/B] I've shown that it has an upper bound and is monotonic increasing, however it is to...
  48. F

    Infinite series as the limit of its sequence of partial sums

    In my book, applied analysis by john hunter it gives me a strange way of stating an infinite sum that I'm still trying to understand because in my calculus books it was never described this way. It says: We can use the definition of the convergence of a sequence to define the sum of an...
  49. Matejxx1

    What Values of x Allow Convergence in a Geometric Sequence of Sine Functions?

    Homework Statement given a geometric sequence sin(x),sin(2x), . . . c) find for which values of x∈(0,π) this sequence converges and calculate its limit Homework Equations |q|<1 or -1<q<1The Attempt at a Solution Ok so in part a) and b) i calculated the quotient and found out that...
  50. sevenperforce

    Stellar-mass black hole formation sequence

    I feel like this could go in quite a few of the Physics subforums (Quantum Physics, Beyond the Standard Model, Special and General Relativity, or High Energy, Nuclear, Particle Physics) instead of Astronomy and Cosmology, but hopefully this will work. This is my first question I've posed here...
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