Limits Definition and 1000 Threads

Els Límits (Catalan pronunciation: [əlz ˈlimits]) is a Spanish village, a civil parish of the municipality of La Jonquera, situated in the province of Girona, Catalonia, in Spain. As of 2005 its population was of 115. Its Spanish name is Los Límites.

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  1. H

    I just have a question about Uniqueness of Limits with divergent sequences.

    Homework Statement I'm supposed to answer true or false on whether or not the sequence ((-1)^n * n) tends toward both ±∞ Homework Equations Uniqueness of Limits The Attempt at a Solution I did prove it another way, but I would think that uniqueness of limits (as a definition...
  2. G

    Evaluating Limits Homework: t^2+1

    Homework Statement \lim_{x\rightarrow3} \stackrel{(t+1)^2}{(t^2+1)} Homework Equations The Attempt at a Solution if the bottom was t^2 - 1 i could factorise and cancel but when its t^2+1 I am not sure how to go...
  3. K

    Limits at infinity, lim xF(x) = L then lim (f(x)=0

    Homework Statement show that if F:(a,∞) -->R is such that lim xF(x) = L, x --> ∞, where L is in R, then lim F(x) = 0, x --> ∞. Homework Equations The Attempt at a Solution Let F:(a,∞) →R is such that lim xF(x) = L, x → infinity, where L is in R. Then there exists an α> 0 where given ε...
  4. lonewolf219

    Limits with two variables, explain why limit DNE

    Homework Statement (Sorry, having problems with math symbols) lim f(x,y) [(x^4)y]/(x^8+y^4) (x,y)→(0,0)Homework Equations Compare limits when a.) y=x b.) y=x^4The Attempt at a Solution The solutions are a.) limit approaches 0 b.) limit approaches 1 I think I understand in...
  5. C

    Limits to infinity with natural logs

    Homework Statement I'm having trouble calculating these limits. Homework Equations none The Attempt at a Solution 1. lim...((lnx)^5)/(x)= x->infinity (((lnx)^5)/x)/(x/x)= (((lnx)^5)/x)/1= How do I calculate from here? 2.lim ...(14lnx^2)/(6lnx^3)=...
  6. F

    MHB Fixing Limits: Ensuring Correct Solutions with Proper Resolution Techniques

    I know that the solution is correct. But i do not know if i resolved it in the correct way. The images are attached.
  7. C

    Calculating limits to infinity

    Homework Statement Can someone tell if if these look right? Homework Equations none The Attempt at a Solution 1. lim (lnx)^5/x = x->infinity 5lnx/x = (5lnx/x)/(x/x)= (5lnx/x)/1 = 0/1 = 0 2. lim sinx/x^2= x->infinity (sinx/x^2)/(x^2/x^2)=...
  8. F

    How to Calculate the Fatigue Limit of Leaf Springs?

    Hi to all. How would I go about calculating the fatigue limit of leaf springs? Is there an equation out there in the form of N, cycles to failure= f(variables, material properties) Or will I have to use the Stress equations for leaf springs and use that stress value and then...
  9. C

    MHB How Do You Calculate the Limit of M*exp(D*exp(c*t)) as t Approaches Infinity?

    Please could someone assist me with this question Compute the limit of lim t→∞ p(t) where p(t) = M*exp(D*exp(c*t))
  10. N

    The Real Importance of Limits in Calculus

    The "importance" of Limits Hey, I am a student in the physics and engineering fields. I have been doing calculus for two years. I understand that the limit is, in a sense, the "building block" of calculus. Differentiation and the derivative is defined by calculating the difference quotient...
  11. B

    Problem on limits from chemistry

    I've been doing some chemistry, and come up with a confusing problem that I can't seem to solve. It's a problem I made up while trying to understand the Gibbs Free Energy, but I will try to phrase it solely as a calculus question. It is known that \Delta G + \epsilon \Delta S < 0 and that...
  12. T

    Is There an Alternative Method for Proving a Limit Involving e and ln?

    Homework Statement Show that lim (x,y) → (a,0) e^(x ln y) = 0 \foralla > 0 Homework Equations The Attempt at a Solution I've tried looking at lim (x,y) → (a,0) x ln y seperately. lim(x,y) → (a,0) x ln y = lim(x,y) -> (a,0) x * lim(x,y) → (a,0) ln y...
  13. C

    Limits in infinite unions of sets

    Suppose I define sets D_n = \lbrace x \in [0,1] | x has an n-digit long binary expansion \rbrace . Now consider \bigcup_{n \in \mathbb{N}} D_n. This is just the set of Dyadic rationals and therefore countable for sure. Now for the question: is this equal to \bigcup_{n = 0}^{\infty} D_n...
  14. Z

    Fourier transform - what integral limits

    Find the Fourier transform of the unit rectangular distribution f(t) = 1 for ltl<1 else 0 Since e-iωt is zero except for t in ]-1;1[ it must be an integral over this interval. But should I take the boundaries as -1 and 1? Because they are not included in the interval where e-iωt is not zero but...
  15. S

    Partition sum of particle, high/low temperature limits

    Homework Statement We have a single particle that can be in one of three different microstates, \epsilon_0, \epsilon_1 or \epsilon_2, with \epsilon_0 < \epsilon_1 < \epsilon_2. The particle is in thermal equilibrium with a heat bath at temperature T. 1) Calculate the canonical partition...
  16. B

    Need help evaulating a few limits

    I made up this limit problems trying to understand something in chemistry, so they may not necessarily have any answer. I am not sure how to evaluate them analytically. Not sure how L'Hopital's Rule would work here either. (\lim_{V→50^{-}}-log(\frac{50-V}{10(V+50)}))...
  17. M

    Proving Limits Do Not Exist Using Two Path Test

    Homework Statement Use the two path test to prove that the following limits do not exist.Homework Equations \lim_{(x,y)\rightarrow{(0,0)}}\frac{4xy}{3x^2+y^2} The Attempt at a Solution The book that I am using introduces the Two Path Test theoretically but does not show an example of how to do...
  18. M

    Limit involving sin at x=pi/6: Solving with Substitution Method

    Homework Statement find the limit: \lim_{x\rightarrow\frac{\pi}{6}}\frac{2sin(x)-1}{6x-\pi} The Attempt at a Solution Any starters please, I've tried the substitution method but went nowhere.I did x=(pi+h)/6. I still get 0 over something which is zero and i know that is not correct.
  19. M

    Limits with sine and square roots

    Homework Statement solve the limit: \lim_{x\rightarrow1}\frac{sin(x-1)}{\sqrt{x}-1} The Attempt at a Solution Is there a way of how i can solve this without using l'hospital's rule or taylor series?
  20. M

    Limits with Trigonometric Functions and Polynomials

    Homework Statement solve the limit: \lim_{x\rightarrow0}\frac{2cos^{2}(x)-cos(x)-3}{x^{2}} The Attempt at a Solution Ok so i factored out the numerator, but i don't know where to go from there any help please...
  21. M

    Calculating Limits Involving Cosine: Is My Approach Correct?

    Homework Statement find the limit of : \lim_{x\rightarrow0}\frac{\sqrt{5-cos(x)}-2}{x^{2}} Homework Equations The Attempt at a Solution I multiplied the numerator and the denominator by the conjugate of the numerator and i got : \frac{1-cos(x)}{x^{2}(\sqrt{5-cos(x)}+2)} then: i divided...
  22. S

    Integration, u substitution with limits

    Homework Statement find ∫x/√(x+1).dx with limits 1 & 0 using substitution x = u^2 -1 Homework Equations The Attempt at a Solution dx = du x = u^2 -1 u = √( x+1) sub limits of 1 & 0 into u. Hence new limits of √2 & 1 Therefore, ∫ u^2 -1/ u = ∫ u - 1/u =...
  23. M

    Multivariable limits, how to show existence or non-existence

    Homework Statement lim(x,y)->(1,0) of ln((1+y^2)/(x^2+xy)) Homework Equations The Attempt at a Solution Used two paths, x=1 y=0 both gave my lim=0 so I tried x=rsin y=rcos, in attempt to use ε-δ to prove it. got to ln((1+r^2sin^2)/(r^2cos(cos+sin))) not sure where to go...
  24. M

    How to Solve Trigonometric Limits Using l'Hopital's Rule

    Homework Statement solve the following limit: \lim_{x\rightarrow0}\frac{x+sinx}{2x-sin3x}The Attempt at a Solution I know the principle of solving all sorts of limits but not trig limits, and since we just started trig limits it's still not clear to me, but i think to solve it we have to...
  25. S

    How do I Integrate this u substitution with limits.

    Homework Statement Find ∫e^x/ (1+e^2x). dx , with limits ln 2 & 0 given u= e^x Homework Equations The Attempt at a Solution u= e^x du/dx = e^x dx= du/e^x sub limits of ln2 & 0 → u Hence, limits 2 & 1 Therefore, ∫u* (1+e^2x)^-1* du/e^x = ∫ u/ (u + e^3x) = ∫...
  26. S

    Integration, u substitution with limits

    [b]1. Homework Statement Evaluate ∫ 3x /(3x+1)^2.dx , with limits 1 & 0 using the sustitution u = 3x+1 Homework Equations The Attempt at a Solution u= 3x+1 du/dx = 3 dx = du/3 Therefore, ∫ 3x*(u)^-2 * du/3 = ∫ x* (u)^-2 Since u = 3x +1 Therefore, x =...
  27. L

    Limits & derivative of absolute value of x

    For absolute value of x, f(x) = lxl To prove continuous, I can express it as a piecewise function of x if x>0 and -x if x<0 and then I can take the limit of each as x approaches 0 from the negative and positive sides. Both limits give zero, and f(0) gives zero, so continuity is...
  28. T

    Calculating limits with trigonomerty

    i am very confused about these problems, my teacher is hard to understand. a)lim x^2+x+2/x^2-5x+6 ..x->3 b)lim (1/x)-1/x^2-1 ..x->1 c)lim x^2+2x-6/x^2+3x-2 ..x->2 d)lim x^2tanx ..x->0 e)lim x^2sec^2xcot^2x ..x->0 f)lim x^2sin(1/x) ..x->0 g)lim x^2/sin^2x...
  29. J

    Indeterminate Limits (L'Hopitals Rule)

    Homework Statement Hey Everyone , i have 4 L'Hopital's rule problems that i am totally stuck on, and hints would be greatly appreciated. Ill just put all 4 here, and any help would be great. 1. lim x->a+ (cos(x)ln(x-a)) / ln(e^x - e^a) Okay, so with this one i determined that it has...
  30. F

    Uniqueness of Limits of Sequences

    Here is the proof provided in my textbook that I don't really understand. Suppose that x' and x'' are both limits of (xn). For each ε > 0 there must exist K' such that | xn - x' | < ε/2 for all n ≥ K', and there exists K'' such that | xn - x'' | < ε/2 for all n ≥ K''. We let K be the larger...
  31. T

    Absolute Value of Limits Proof

    Homework Statement Show that if bn→b, then the sequence of absolute values |bn| converges to |b|. Homework Equations The Attempt at a Solution I've been proving various properties of limits, including product of limits and sum of products, but have been having trouble making...
  32. N

    Can better sensors extract more info from old lens w/o limits?

    This problem I encountered in my photography forum. A new model of camera comes out with a much higher megapixel sensor (Nikon D800, 36mpix). I argue that such sensor will need new lenses to be meaningful. Others claim that a given lens performance (here resolution) is always utilized by a new...
  33. S

    Testing the Limits of Special Relativity: Questions and Insights

    1. Consider a correlation function between two points `A(x1,t1)` and `B(x2,t2)`, we need to integrate over paths which could be infinite long. But the time length `(t1-t2)` is finite, so if A and B are the coordinates of one single particle, then all of the paths from A to B should be time-like...
  34. Q

    Are There Limits to Human Learning?

    I mean I know that because there are physical limitations that there has to be some kind of limitation, but it seems like it could in a way go on forever, like you could just keep learning and generalizing previous information or learning and sort of putting it in your subconscious or...
  35. F

    Evaluating Limits: Question & Solution

    Homework Statement Question : lim_{x\rightarrow2}f(x)Homework Equations The Attempt at a Solution I am really very confused about this. I know limits are the "intended height of the function". So, what if the function is like this? I know for one that this is a function since it passed the...
  36. ElijahRockers

    CALC III Finding limits for a function of two variables.

    Homework Statement Find the limit of f(x,y) = \frac{x^{2}-y^{2}}{\sqrt{x^{2}+y^{2}+81}-9} as (x,y) \rightarrow (0,0) The Attempt at a Solution Ok, I looked at the examples in the book, and it seems pretty straight forward... I first look at f(x,0) to see what happens as we approach...
  37. V

    What is the Limit of (1+x)^(1/x) as x approaches 0?

    Homework Statement see attachment Homework Equations limx->0(1+x)1/x=e The Attempt at a Solution step 1: take log in both sides of an=...(as in function). step 2: multiply and divide it by 2n inside the log. step 3: there are n terms in multiplication so substitute 2(of...
  38. R

    Are there limits to our imagination within the universe?

    Everything that exists, had existed and will ever exist are all contained within the universe... (Leave out the parallel universes concept for now).. So that means our imagination also exists within the universe... I mean with our mind we think and our mind is contained within the...
  39. A

    Help understanding what limits are

    Homework Statement http://www4c.wolframalpha.com/Calculate/MSP/MSP18091a03ad70feibdhb300005da572897hebg236?MSPStoreType=image/gif&s=52&w=143&h=42 Homework Equations lim x->2+ (x^2 - 3x + 2) / (x^3 - 4x) The Attempt at a Solution I plugged in 2 for x and it was 0/0 so then I...
  40. N

    Limits involving logs, negative inf and probabilities.

    Hello! I am playing around with an equation (i.e. it's not a textbook question), and I arrived at the following problem: The equation is: A = -1*\sum_{i=1}^{N}*\log_{N}(P_{i})*P_{i} Pi is less than or equal to 1 and more than or equal to 0, and is a probability of finding an object in a...
  41. The Chaz

    MHB Limits Involving Absolute Value: Solutions & Explanations

    Let f(x) = |x|/x a. What is the limit of f, as x approaches 0 from the right? b. What is the limit of f, as x approaches 0 from the left? c. Hence, what is the limit of f, as x approaches 0? ------------------------------ The best way to evaluate limits involving absolute values is to use...
  42. T

    Path Integral example, analysis of integral limits for K-G theory

    In general I find in books that the path integral approach is an equivalent alternative of the hamiltonian approach for QFT (and for QT in general, but my concern is with QFT). There I usually find that this method is usually developed in a formal way and used to derive Feynman rules, gauge...
  43. B

    The precise definition of limits

    If you look at this text towards the very end they are dividing by 2. I don't see why.
  44. Q

    Limits with sinx where x tends to infinity help.

    Homework Statement http://prikachi.com/images/26/4273026B.gif Homework Equations The Attempt at a Solution I'm having problems in solving the limit which is shown on the gif file . As you see I use L'Hopital's rule 2 times and I get to a point when I should divide -sinx with sinx...
  45. T

    Substitution changes limits of integration?

    I'm working through rewriting the gamma function as an infinite product, but my question is just about a specific substitution that was made in my textbook. They took the equation: \Gamma_ n(z)=\int_0^n t^{z-1} (1-\frac{t}{n}) ^ndt for Re(z)>0 and n greater than or equal to 1. and made the...
  46. T

    Graphing f(x) = e^x/x and Testing for Infinity

    When sketching a graph I'm told to assume that the expression: f(x) =( e^x)/x Tends towards the infinite as x tends towards the infinite. Can someone show me how to check this? Thanks
  47. J

    Fourier series of complex numbers with diffrent limits of integration?

    Fourier series of complex numbers with diffrent limits of integration? Dear all, i don't know how to simplify a COMPLEX NUMBER Fourier series with LIMITS OF INTEGRATION that are not complementary. I MEAN limits LIKE this X to -X being easy to solve and SIMPLIFY but Not X to -Y or...
  48. A

    Confused about Limits in Algebra? Let's Clear Up Some Doubts!

    I have the following doubts. Please help me get through them... (1) Is there any difference between the terms 'limit does not exist' and 'limit is not defined'? (2) For a limit to exist does it have to be a finite number? (3) When we do the algebra of limits as lim (x->a) [f(x) + g(x)]...
  49. J

    Right limit of a composite function. Original functions limits are known.

    Homework Statement If \lim_{x\rightarrow 0+}f(x)=A and \lim_{x\rightarrow 0-}f(x)=B find \lim_{x\rightarrow 0+}f(x^{3}-x) Homework Equations The Attempt at a Solution I don't have one. I am dumbfounded. Mostly i have been trying to understand the meaning of the composite...
  50. P

    Biological limits on pepper arms race?

    In the last year or so, there has been a breeder arms race to produce the hottest pepper. The peak has gone up a little over 1 million scoville to over 1.5 million scoville in a short time. Since pure capsaicin is 16 million scoville, there is a well defined upper limit. I don't know the...
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