Limits Definition and 1000 Threads

  1. KiNGGeexD

    L'Hospitals Rule for finding the limits of a function

    Above is a function which I have been given to take the limits of, now we were briefly introduced to L'Hospitals rule and given this example! Here is what I have done so far...l..Basically I know that I have to take the derivatives of each of the functions in the quotient and then tend it to...
  2. X

    What would the new limits be for this integral?

    I am working on an physics problem and it has boiled down to this integral. \int_{0}^{∞} r e^{-\frac{1}{2 r_0}(r-i r_0^2 q)^2}dr I found that if I make the substitution ##u=r-i r_0^2 q##, then I can do the integration, but I am a little confused about what the limits would be in terms of...
  3. N

    Limits if polar coordinates (conceptual explanation)

    1. Homework Statement [/b] Suppose the lim(x,y) →(0,0) (xy)/SQRT[x^2 + y^2] if it exists find the limit. The Attempt at a Solution x = rcosΘ y = r sinΘ r = SQRT[x^2 + y^2] ∴ lim[SUB]r → 0 (r2cosΘrsinΘ)/ r = rcosΘsinΘ \leq r and so -r \leq(xy)/SQRT[x^2 + y^2] \leq r ... ... I can...
  4. C

    Limits of convergent sequences

    Homework Statement an= (n/n+2)^n ANS: 1/e^2 The Attempt at a Solution I was told this was convergent and I need to find the limit of the sequence. How do I do this, as I seem to keep getting that this is divergent. Isn't it divergent to infinity? Or am I missing something?
  5. C

    Limits of convergent sequences

    Homework Statement an= (n/n+2)^n The Attempt at a Solution I was told this was convergent and I need to find the limit of the sequence. How do I do this, as I seem to keep getting that this is divergent. Isn't it divergent to infinity? Or am I missing something?
  6. B

    Is there a Leibnitz theorem for sums with variable limits?

    Is there a "Leibnitz theorem" for sums with variable limits? Wikipedia says that if we want to differentiate integrals where the variable is in the limit and in the integrand, we can use Leibnitz theorem: But what if I need to integrate a function defined like this:\Sigma_{I(x)}[f(x,t)]...
  7. anthonyk2013

    Integration by partial fractions with limits

    \int (x+1/x2-3x-5)dx I can't put the limits on the integral sign, 5 is the top limit and 3 is the bottom limit. I can solve using partial fractions ok but I have never solved with limits before. Where do the limits come in, do I need them at the start or can I factorise as usual and use...
  8. T

    Limits lim x→3+ = 81-x4/(x2-6x+9)2

    Homework Statement Calculate the limit, if it exists: lim x→3+ = 81-x4/(x2-6x+9)2 Homework Equations The Attempt at a Solution -(x4-81)/(x-3)(x-3) = -(x2-9)(x2+9)/(x-3)(x-3) = -(x-3)(x+3)(x2+9)/(x-3)(x-3) = -(x+3)(x2+9)/(x-3).....I'm stuck here and don't know what to...
  9. R

    Exploring Limits: Approaching (0,0) from Different Paths

    Homework Statement By considering different paths, show that the given function has no limit as (x,y) \rightarrow (0,0). f(x,y) = x4/(x4 + y4) Homework Equations The Attempt at a Solution My instructor taught me this process a while back and am unsure if it fits for this...
  10. B

    Limits of "Proper" Function Approach to Banach Spaces

    Hello, I have seen (in H Cartan's differential calculus) a proof that if F is a Banch space, L(E,F) where E is some vector space, is also a Banach space. One of the main points of the proof is based on the behaviour of a function being "proper" (continuous) on a ball of arbitrary radius "n"...
  11. M

    Integration Limits: Is Upper Limit Always Greater Than Lower?

    is the upper limit always greater than the lower limit in integration? what should be the limits if we need to calculate total work done in bringing a mass from infinity to distance r from earth.
  12. JasonHathaway

    Determining double integral limits

    Homework Statement Evaluate \iint\limits_S \vec{A} . \vec{n} ds over the plane x^{2}+y^{2}=16, where \vec{A}=z\vec{i}+x\vec{j}-3y^{2}\vec{k} and S is a part from the plane and R was projected over xz-plane. Homework Equations Surface Integral and Double Integration.The Attempt at a...
  13. P

    MHB Constants & Limits: Integration & Anti-Derivative Q

    So I have this question: And I just want to check my answer. Am I right? I think that the first formula is the theorem of integration so a and b are limits o integration and I'm not sure about the second formula, I think it's the anti derivative formula making that the anti derivative...
  14. JasonHathaway

    Double integral limits from an equation?

    Hi everyone, I've the equation x+y=6 (it's a surface equation which I'll integrate over) and the following integral limits is what I suppose to get it from the equation: \int\limits_0^6 \int\limits_0^{6-x} What's the trick here?
  15. G

    Left hand and right hand limits

    Problem statement What is the left hand and right hand limit of 1/x^2 -4 at its vertical asymptote? Revelant equations None Attempt at a solution It's vertical asymptote are 2 and -2. I have attached my work . I understand it however at the back of the book it says the left hand limit at...
  16. E

    Change of Variables - Finding New Limits

    Homework Statement Integrate the following over the set E. \int_E \frac{2x+y}{x+3y} dA Bounded by the lines: y = −x/3+1 y = −x/3+2/3 y = −2x y = −2x + 1 Homework Equations None. The Attempt at a Solution I can up to the same point everytime, but always get stuck on finding the new...
  17. 9

    Convergent limits for sequences: picture terms

    A limit of a sequence is definitely convergent if: If for any value of K there is an N sufficiently large that an > K for n > N, OR for any value of K there is an N sufficiently large that an<±K for n > N My only question is what exactly are K, N, an and n? What values are they? How would...
  18. D

    How to Find the Limit of sin(3x²)/(8x) as x Approaches Zero?

    1. what would be the limit?? without using the L'Hopital's rule lim_(x-0) (sin(3 x^2))/(8 x) the limit of sin(3x^2) divided by 8x as x approaches zero 2. Limits of trignometric functions 3. The Attempt at a Solution I tried factoring out the 1/8, but...
  19. vanceEE

    Limits of Integration for Revolving Region R around the y-axis

    Homework Statement Let f be the function defined by $$ f(x) = - ln(x) for 0 < x ≤ 1. $$ R is the region between the graph of f and the x-axis. http://learn.flvs.net/webdav/educator_apcalcbc_v10/module08/imgmod08/08_10_01.gif b. Determine whether the solid generated by revolving region R...
  20. N

    Evaluating Limits: Understanding the Solution to a Challenging Calculus Problem

    Hello, I am struggling with limits in my calculus course and would appreciate a bit of help. The question is: \lim_{x→-6}\frac{x^2-8x+12}{x^2-x+30} So far I have tried the factoring and substitution methods but have not managed to match the answers given by online equation solvers. For...
  21. applestrudle

    How to Choose Limits for Double Integrals?

    Homework Statement ∫∫ydxdy over the triangle with vertices (-1,0), (0,2), (2,0) Homework Equations I did it like this and got the right answer: ∫dy ∫ydx this first: ∫ydx from x = (y-2)/2 to x = 2-y then ∫dy from y = 0 to y = 2 I got 2 which is correct but when I...
  22. E

    Question about absolute value limits?

    When do you check the limit from the right and left of a limit with an absolute value in the numerator or denominator? For example, why do you check the limit from both sides of: Lim x -> 3/2 (2x^2-3x)/absolute value(2x-3) But only the left side of: limit as x approaches -2...
  23. E

    How Should I Find Limits for Variables u and v in Calculus?

    Hi! Here is my task: Here is my attempt of solution: Does it make sense? How should I find limits for u and v? I appreciate any help!
  24. P

    Using limits to find asymptotes.

    1. $$f(x)=x-\frac{1}{6}x^2-\frac{2}{3} lnx$$ Homework Equations limits The Attempt at a Solution I know there is a vertical asymptote at x=0 because all values of x have to be greater than x. The answer says that there is no horizontal asymptote, but I don't know how it...
  25. binbagsss

    Basic epsilon and delta proofs, limits, quick questions.

    I am trying to check whether lim h→0 (R(h)/||h||) =0 or not. I am working in ℝ2. h=h1e1+h2e2** => ||h||=(h1^2+h2^2)^1/2 I am using the definition that (R(h)/||h||)<ε * whenever 0<|h|<δ for all h. Example 1 (R(h)/||h||)=h1h2/(h1^2+h2^2)^3/2 I can see that the denominator dominates...
  26. binbagsss

    How to prove that fn converges uniformly on {z:|z|≤p}

    I am trying to show {fn} converges uniformly on {z:|z|≤p}, where p is postiive real number. and fn(z)=sin(z/n). I am able to follow parts of my books method, but don't understand a couple of the inequalities...(my trouble lies in the inequalities rather than the main concepts involved in the...
  27. J

    Limits of Integration Variable

    Knowing that the limits of integration of a any function, for example: \int_{-\infty}^{+\infty}\delta (x)dx=1 I know that's correct call your primitive through the limit superior as a variable, so H(x)=\int_{-\infty}^{x}\delta (x)dx But, and if I want to describe your primitive through the...
  28. H

    Evaluate the following limits if it exist

    Homework Statement evaluate the following limits if it exist lim x sin1/x and limit x sin 1/x x→0 x→∞ Homework Equations The Attempt at a Solution Someone have told me that I should let t=1/x and rewrite the limits.However, once I rewrite the...
  29. J

    Is it possible to manipulate limits in equations?

    I believed the definitions of derivative that we know was really definitions f'(x_0)=\lim_{x\rightarrow x_0}\frac{f(x)-f(x_0)}{x-x_0} f'(x_0)=\lim_{\Delta x\rightarrow 0}\frac{f(x_0+\Delta x)-f(x_0)}{\Delta x} But not, is one definition, just use the equality bellow in equations above... \\...
  30. F

    Optimized "Homework Solutions for Hard Limits

    Homework Statement 1. lim as n approaches infinity of ((n+1)^5-(n-1)^5)/n^4 2. lim as n to infinity (n!)^2/(2n)!Homework Equations The Attempt at a Solution 1.I split it up, got (((n+1)/n)^4)*(n+1)-(((n-1)/n)^4)*(n-1). I try to simplify that down to (n+1)-(n-1) and got 2 as my answer, since the...
  31. S

    MHB Evaluating Limits using L'Hospital (2)

    lim x--> 1 \frac{x^4 - 3x^3 + 3x^2 - x}{x^4 - 2x^3 + 2x - 1}I got \frac{0}{6} = 0
  32. S

    MHB Evaluating Limits using L'Hospital

    Need someone to check my work.lim t -> 0 \frac{e^{2t} - 1}{1 - cos(t)} after I took the derivative twice I got \frac{2}{0} = undefined?
  33. I

    Limits of integration question (double integral)

    so in the image in the link below, i don't understand a couple of things: 1.) the center of the cylinder is off to the side and not at the center. where/how in the problem are we taking this into account? because it should definitely affect the volume under the parabaloid right? 2.) most of...
  34. G

    MHB Help with Calculating Limit Problem

    hi , i have a problem that i couldn't solve , i know its limit should be 1 because i looked up in the helping part of my manual . i must calculate : LIM (when n goes to infinit) ( (n^2 + n + 1) * ln( (n+1)/(n+2) ) * ln ( (2n+1)/(2n+3) ) ) i know i should use the case of 1 ^ infinit but i can't...
  35. K

    How Do You Analyze the Function \( f(x) = \frac{x-4}{x^3} \)?

    Homework Statement I am to explain all intercepts, critical numbers, extrema, inflection points, and asymptotes of the function f(x)=(x-4)/x^3. 2. The attempt at a solution a) The y-intercept does not exist, as the domain of the function is all real numbers except x=0. Solving the...
  36. Q

    Finding Bounds of Integration for Integral of Cos(2+x)

    Homework Statement http://i.minus.com/jJQzZXoxXFqEB.png Homework Equations (b-a)/n = Δx The Attempt at a Solution I know how to express the sum as an integral .. almost. It is the integral of cos(2+x) with respect to x. However, what are my bounds of integration? I know that b-a must...
  37. Saitama

    Given general term - find limits and comparison

    Homework Statement Let ##\displaystyle a_n=\frac 1 2+\frac 1 3+...+\frac 1 n##. Then A)##a_n## is less than ##\displaystyle \int_2^n\frac{dx}{x}##. B)##a_n## is greater than ##\displaystyle \int_1^n\frac{dx}{x}##. C)##\displaystyle \lim_{n\rightarrow \infty} \frac{a_n}{\ln n}=1##...
  38. D

    Estimating the fraction of ejecta travelling between velocity limits

    First of all, THIS IS NOT HOMEWORK. It's related to my research. And forgive me if this is rather elementary (sadly, I was something of an underachiever at school, which has left some gaps in my maths education that I've been working on since I returned to education) but I have a question...
  39. I

    Expressing the limits of integration for radius in polar coordinates

    i'm trying to integrate some some function bounded by the x-y domain of x2+y2=6y which is a circle on the x-y plane shifted upward where the outer part of the circle is 6. i'm trying to integrate a double integral.. ∫∫f(x)rdrdθ i don't know how to express my limits of integration for r...
  40. Q

    Trig Limits: Solving 0cot(0) - 1 = 0

    Homework Statement http://i.minus.com/iCJwlfzPc5fRu.png Homework Equations This feels like a movie requiring the suspension of disbelief. The Attempt at a Solution cot(x) = cos(x)/sin(x). cot(0) = 1/0 Right? How in the world then is 0cot(0) - 1 = 0? That should be infinity minus 1.
  41. H

    Removable Discontinuity of f(x)=(4-x)/(16-x^2)

    removable discontinuity Homework Statement the following function f(x)=(4-x)/(16-x^2) is discontinuous at? i got at -4 but some of my friends say its 4, -4 how is that possible
  42. P

    Finding Limits: lim θ→0 \frac{sinθ}{θ+tanθ}

    1. lim θ→0 \frac{sinθ}{θ+tanθ} Homework Equations lim x→0 \frac{sinx}{x}=1 lim x→0 \frac{cosx-1}{x}=0 The Attempt at a Solution lim θ→0 \frac{sinθ}{θ+sinθ/cosθ} lim θ→0 \frac{sinθ}{(θcosθ+sinθ)/cosθ} lim θ→0 sinθ × \frac{cosθ}{θcosθ+sinθ} lim θ→0 \frac{θcosθ}{θcosθ+sinθ}...
  43. N

    How to manipulate limits in this integral

    hi all, I have following integral and i was wondering if i can manipulate limits to simplify it. ∫^{t}_{0} P(τ) exp( - a ∫^{t}_{τ} P(u) du) dτ I know that the answer is \frac{1}{a} - \frac{1}{a} exp( - a ∫^{t}_{0} P(t) dt) But don't know how to get there. Thanks in advance.
  44. M

    L'Hospital's rule to find limits

    Homework Statement Find the limit, using L'Hospital's rule, if appropriate. lim lnxtan(pix/2) x->1^+Homework Equations The Attempt at a Solution http://imgur.com/gbhQutU I've done this question and gotten the correct answer by making lnx the numerator and 1/tan(pix/2) the denominator, but...
  45. T

    MHB Another two limits at infinity

    I know I am already boring with limits,but i again have two of them to deal with and i don't know how... 1. \lim _{n \to \infty} \frac{5^{n^+1}-2*5^n+5^{n-1}}{3^{n+1}-3^n} 2. \lim _{n \to \infty} \frac{\sqrt[3]{n^4}+\sqrt{n}+1}{\sqrt[6]{n^4}+\sqrt[3]{n}+2}
  46. T

    MHB How do I solve limits at infinity with similar problems on my exam?

    Again i have two similar problems: \lim _{n \to \infty} \frac{3n-\sqrt{4n^2+n}}{3n+\sqrt{4n^2-n}} \lim _{n \to \infty} \frac{\sqrt{9n^2-n}-2n}{\sqrt{9n^2-n}+2n} Those kind of problems will be on my exam,which is very close,and i don't get it how to deal with this limits... I just say...
  47. L

    Interchaning Limits and Inner Products

    Everything here is in a Hilbert space. If x_n\to x and y_n\to y in norm, then under what conditions does <x_n,y_n>\to <x,y>? Is this always true, and why? Does anyone have a source?
  48. C

    Is There a Macro Version of the Planck Length?

    Hopefully this is in the right sub-forum. Anyway, we all know the Planck length placed a limit on how small something can be and still make physical sense. Is there a macro version of this? Is it possible that the universe/multiverse, or some other macro object, can only be so big before it...
  49. B

    Why Can't We Redefine a Function at Its Undefined Point?

    when we find a limit for an undefined point on a curve , X^2 - 1 / x - 1 at x = 1 for instance we reshape the equation without actually changing anything to find the limit at this point . why can't we do that to define the point on the function ? i mean clearly if we say F(x) = x^2 - 1 / X -...
  50. M

    What is 0 multiplied by infinity in limits?

    If you have f(x) = 1/x and g(a) = (cosx - 1)/x and then y = [limx→0 f(x)][limx→0g(x)], the two individual limits equal 0 and infinity, respectively. Since these are limits and only approach these values, would the multiplication of the two limits equal 0, infinity or something else?
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