Root Definition and 918 Threads

  1. T

    Limit of the nth root of (n ln n)

    Homework Statement Find lim_{n \rightarrow \infty} \sqrt[n]{n ln(n)}. Do not use L'Hospital's Rule or Taylor Series. Homework Equations The Attempt at a Solution I suspect I need to set up some inequality for this and then apply Squeeze Theorem. But I can't find any inequality...
  2. J

    Easy question about the root (of a real number)

    [SOLVED] Easy question about the root (of a real number) Hi, I'm a bit embarresed to ask this but does anybody know how to get this: \sqrt{3 - 2\sqrt{2}} = \sqrt{2} - 1 ?
  3. DocZaius

    Notation for Principal Square Root?

    Hello, I was just wondering if there is a special notation for a principal square root... I suppose using absolute value would work.. \left|\sqrt{9}\right|=+3 But it doesn't seem as fitting as an actual special square root symbol. Maybe something like this? \sqrt[+]{9}=+3 Also...
  4. I

    Square root of Dirac Delta function

    Homework Statement I wonder how to deal with the square root of Dirac Delta function, \sqrt{\delta(x)}. Actually, this comes from a problem which asking readers to calculate the wave function of a free particle and of a harmonic oscillator at time t, provided that the wave function at time...
  5. J

    Square root of 1 with mod how to prove it?

    I know that if n is odd and has k distinct prime factors, then the number of roots, x^2 = 1 (mod n), is equal to 2^k. However, I don't know how to give a formal proof to it. I simply want to bypass the generalized form x^2 = a (mod n). How can I prove it directly? Thank you.
  6. W

    Question about the limit of a square root

    Hello! I got the following exercise: \frac{lim}{x\rightarrow6-} {\sqrt{3x-18}} Now, since I need to evaluate the limit from the function coming from the left to the right that means that I can evaluate the function using x as a value very close to 6, but not six, right? So, since I would...
  7. S

    Proving a limit theorem of a sequence (square root)

    Homework Statement given the sequence {a_n} converges to A (non zero), show sqrt(a_n) = sqrt(A) Homework Equations The Attempt at a Solution I've tried to expand |sqrt(a_n) - sqrt(A)| as |a_n - A|\|sqrt(a_n) + sqrt(A)| since that gives me the numerator to work with, but I can't...
  8. N

    Is there a way of proving that all positive numbers have a real square root?

    Homework Statement My prof showed us the proof that sqrt2 is not a rational number. She said, however, that we haven't proved that it is irrational, because we haven't proved that sqrt2 exists. How would we go about proving this? Homework Equations N/A The Attempt at a Solution...
  9. Y

    Integrate x^2 /square root (x^2 +1)

    Hi, the question is integrate x^2 /square root (x^2 +1). I tried to do it but i was stucked in the very last step.at the end,I got x/2 * cosh(arcsinh x) + 1/2 * arcsinh x - arcsin (square root (x^2 + 1)) +C. I dunnoe how can I simplify cosh(arcsinh x) into simplier form in term of x. I hope...
  10. S

    How Do I Solve This Complex Square Root Equation?

    Homework Statement Can someone advice me how to solve this square root equation? n_{0}=1.5*10^{15}+\sqrt{(1.5*10^{15})^{2}+[(0.05)n_{0}]^{2}} The answer should be n0=3.0075*1015 I can't figure out how to open up the square root to solve the equation for n0. Stuck here staring at the...
  11. E

    Square Root Method - Fractions

    Homework Statement x^2 - 1/2x - 3/16 = 0 The Attempt at a Solution Actually, I don't know where to start since I have fractions.
  12. E

    Limits of expression with square root

    I am looking at the derivation for an expression that relates the concentration of an oxide to time. It appears that to do this, the author takes the limit of sqrt(A+Bt), where A and B are constants as t approaches zero and infinity. Is there an easy way to do this without making assumptions...
  13. E

    Solve Square Root Method: (x-1)^2 = 4

    Homework Statement (x - 1)^2 = 4 The Attempt at a Solution This is what I've done (x - 1)^2 = 4 Everything inside parenthesis goes to: ^2 x^2 - 1^2 = 4 now we got x^2 - 1 = 4 Now (I think) I use the square root method x^2 - 1 = √4 x^2 - 1 = 2 Now I factorize: (x - 1) (x +1) = 2 This is...
  14. E

    Inverse function containing square root

    Homework Statement Given f(x) = -x2 - 2x + 3, x < -1 Find f-1. Find f-1f. Homework Equations Nil. The Attempt at a Solution Actually I worked out much of the question already, and I already know that f-1f: x -> x. The problem is, I can't seem to get f-1f(x) = x on...
  15. C

    Derivative of a square root fraction. HELP

    Homework Statement What is f'(x) of f(x) 1/sqrt(2x)? 2. The attempt at a solution In applying the problem to the derivative formula: (1 / sqrt(2(x + h)) - 1 / sqrt(2x)) / h I multiplied the problem by a special form of one but that only put the rationals on the bottom of the...
  16. D

    Principal root of a Complex Number

    Homework Statement Find all the roots in rectangular coordinates, exhibit them as vertices of certain squares, and point out which is the principal root. The Attempt at a Solution The problem is (-8 -8\sqrt{3}i)^{\frac{1}{4}} and I found the four roots easily to be \pm(\sqrt{3} -...
  17. T

    Why Can't You Cancel Out the Square Root and Square in a Square Root Problem?

    Homework Statement Can someone explain to me how |-4|= \sqrt{(-4)^{2}} I'm wondering why you can't cancel out the square root sign and the square above the -4, to leave you with -4. The Attempt at a Solution I know this has something to do with the absolute value of -4, being 4, but...
  18. D

    Iterative square root? sqrt(2+sqrt(2+sqrt(

    The other day I was playing with my calculator and noticed that \sqrt{2+\sqrt{2+\sqrt{2+\sqrt{2+...}}}} \approx 2 But, what is that kind of expression called? How does one justify that limit? And, to what number exactly does converge, for example...
  19. K

    Solving Root Finding Problem with Sparse Matrix | Krindik

    Hi, While trying to simplify a solution I came up with the following sparse matrix but don't know how to solve it. [A(t)][X] = 0 $\left( \begin{array}{ccccc} A_0(t) & 1 & 1 & ... & 1 \\ A_1(t) & 1 & 0 & ... & 0 \\ ... & ... & ... & ... & ... \\ A_{n-1}(t) & 0 & ...
  20. W

    How does \sqrt{1+((x^2)/(4-x^2))} simplify to 2 times\sqrt{1/(4-x^2)}?

    1.I can't figure out how the \sqrt{1+((x^2)/(4-x^2))} simplifies to 2 times\sqrt{1/(4-x^2)} I have tried rewriting it in different ways, but I can't see how it simplifies. \sqrt{x^2 + 1/4-x^2}
  21. S

    Norm of a function ||f|| & the root mean square of a function.

    norm of a function ||f|| & the "root mean square" of a function. How do I explain the connection between the norm of a function ||f|| & the "root mean square" of a function. You may like to consider as an example C[0,\pi], the inner product space of continuous functions on the interval [0,\pi]...
  22. N

    Can Ratio and Root Tests Determine the Convergence of Complex Series?

    1. \sum_{n=1}^{\infty}ntan\frac{1}{n} dont know where to start here 2. \frac{1*3*5*****(2n-1)}{n!} \frac{2n-1}{n!} \frac{2(n+1)-1}{(n+1)!}*\frac{n!}{2n-1} \frac{2n+1}{(n+1)(2n-1)} ->0 my book is showing divergence
  23. N

    How can I integrate the composite root integral \int\sqrt{40t^2+e^t^2}dt?

    Homework Statement \int\sqrt{40t^2+e^t^2}dt That should be e^t^2. How would I go about doing this?
  24. J

    Complex Numbers- Square root 3i

    (1- sqrt 3i) ^3 I am having trouble solving the sqrt 3i part. I think I need to use de moivres theorem but I am unsure. If someone could push me in the right direction that would be a massive help. Thanks.
  25. S

    Why the square root of the determinant of the metric?

    Hi, We use as an integration form in Riemannian geometry the covariant \int \sqrt{g}d\Omega I understand how this is invariant under an arbitrary change of coordinates (both Jacobian and metric square root transformation coefficient will cancel each other), what I don't understand is why don't...
  26. K

    Why Am I Stuck on My Root Locus Design Problem?

    Homework Statement The Attempt at a Solution Hi, I’ve been studying Root Loci for almost 3 months now, on and off, so I know most of the methods involved with it. I’m still pretty much new to the subject still as I’ve recently hit a problem with this exercise that I’ve been working...
  27. S

    Find Other Roots of a3-3a2+a+5=0 Given 2-i

    Homework Statement Given one root of the equation, find the others. a3-3a2+a+5=0 Given root: 2-i The Attempt at a Solution I know the answers, which are 2+i and -1. And I understand how to get the 2+i since when you square root anything, the answer can be positive or negative, but I have...
  28. I

    Square root operation and scales

    this is a strange problem easy to solve but I am having trouble understanding it intuitivly. Assume we choose a location point and name it 0. Next, in arbitrary direction and distance we place the number 1. Hence, we have created a scale(number line) that extends as much as we like. Now we...
  29. D

    When should the plus/minus sign be used when dealing with square roots?

    Ok, I know this question sounds incredibly elementary, but please don't just dismiss it, try to understand what I'm REALLY asking. Ok, say we have x^{2} = 9. I know the answer is x = \pm 3. But I was just thinking about the general rule to this. I was thinking that what really happens is...
  30. F

    How Do You Integrate 1/(x^(1/2) - x^(1/3))?

    Homework Statement \int\frac{dx}{x^{1/2}-x^{1/3}} Homework Equations None The Attempt at a Solution What I did was replace \int\frac{dx}{x^{1/2}-x^{1/3}} with \int\frac{dx}{u^{3}-u^{2}} if u=x^{1/6}. Just to simplify things. And I think that was pointless. Help me out?
  31. D

    Calculating Pressure and Velocity in a Cylinder of Argon: Tips and Tricks

    Root Mean Square Speed... HELP! A 11.0 cm-diameter, 24.0 cm-long cylinder contains 1.80×1022 atoms of argon at a temperature of 52.0 C. What is (Vx)rms, the rms value of the x-component of velocity? What is the rate at which atoms collide with one end of the cylinder? Determine the pressure in...
  32. C

    Integrating the square root of a linear function.

    Homework Statement \int\sqrt{2*x-1} Homework Equations The Attempt at a Solution Homework Statement Obviously this can be fixed with the antiderivative of a linear function with proper constants i.e. \int A\times f(bx + c) = \frac{A}{b} F(bx + c), however my instructor provided...
  33. M

    Is \sqrt[3]{2} Irrational and Cannot be Represented by Rational Numbers?

    Hey guys. I forget where I found this problem but it goes as follows: Prove that \sqrt[3]{2} cannot be represented in the form p+q\sqrt{r} where p,q, and r are rational numbers. It is easy to show that \sqrt[3]{2} is irrational, so it cannot be put in the form m/n, where m and n are...
  34. W

    How Do You Calculate Cube Roots of Complex Numbers in Modulus Argument Form?

    can someone help me solve this question as fasd as possible?? im really headache wif it... thx~~ determine the 3 cube roots of 3-i over 3+i giving the result in modulus argument form,express the principal root in the form a+Jb
  35. D

    How do I find the square root of 3 - 2\sqrt 2?

    Homework Statement Find the square root of 3 - 2\sqrt 2. Homework Equations The Attempt at a Solution I don't really know how to do this quickly. Could this be done by solving x^2 = 3 - 2\sqrt 2? Or should I solve (a + b)^2 = 3 - 2\sqrt 2? By the way, the answer is 1 - \sqrt 2.
  36. T

    I cant understand the meaning of this root

    http://i42.tinypic.com/2yju26p.gif i know that the root supposed to be a distance but i can't see the distance from where to where?? the charges are not a single point i don't know how they calculate this distance ??
  37. A

    Designing a Cruise Control System Controller with Root Locus Method | Coursework

    Homework Statement I have to design a controller for "Cruise Control System" using Root Locus method. Homework Equations We havnt studied that method yet and nor do I think it is in the course outline. Actually that is why I selected root locus so that I can learn something beyond the...
  38. S

    About the epidermial cell of the root hair.

    Anyone one here, knows any link where there will be a diagram of the epidermal cell of the root hair cell? If not, could you please explain to me everything about the epidermal cell of the root hair.
  39. V

    Efficient Methods for Finding Square Roots without a Calculator

    This has been bothering me for a while now. Without a calculator and without using "guess and check" how can find the square root of a number? For example: 6^{2} = 36 but how can you reverse it and figure out what \sqrt{36} equals? Is there some equation to it or can it only be done using guess...
  40. A

    Standard deviation of root mean square error

    I am comparing two RMS error time-series and I would like to generate error bars on the RMS results. I think the RMS error is a standard deviation of an assumed zero mean process, and I have the gut feeling that this should be the standard deviation of the sample standard deviation. Is that...
  41. B

    Laurent expansion of principal root

    How do I find the Laurent expansion of a function containing the principal branch cut of the nth root? Example: f(z)=-iz\cdot\sqrt[4]{1-\frac{1}{z^{4}}}
  42. K

    What Is the Root of Number Operator in Quantum Mechanics?

    I seen in some paper, there is an matrix whose element has a square root of number operator, e.g. A = \left( \begin{matrix} \alpha & \gamma \sqrt{\hat{a}\hat{a}^\dagger} \\ -\gamma \sqrt{\hat{a}^\dagger\hat{a} & \beta \end{matrix} \right) where \alpha, \beta, \gamma are real...
  43. S

    Integral involving a square root which I can't work out

    Homework Statement Hi, I'm stuck on the following integral. ∫ y / (√(a(y^2)-c)) dy where a and c are constants Homework Equations The Attempt at a Solution I've tried using standard integrals involving square roots in the denominator, but I'm unsure what to do with the y on...
  44. H

    Constructible root from cubic polynomial

    Does x^3 - 3x + 3sqrt(3) = have a constructible root? my solution: suppose a is a constructible root of the equation above. we square both sides to get x^6 - 6x^4 + 9x^2 = 27. since a is constructible, a^2 is constructible as well and we can turn this equation into cubic poly with rational...
  45. Z

    Integral involving sine and root

    Homework Statement \int_0^{\infty} sin(ax) / sqrt(x) dx Homework Equations The Attempt at a Solution I thought of using integration by parts, but that gets me nowhere. I'm not sure how to go about this problem.
  46. L

    U-th root of 1/u as u goes to infinity is 1.

    Is this true? n,m\in\mathbb{N} \lim_{n\to\infty}\sqrt[n]{\lim_{m\to\infty}\frac{1}{m}}=\lim_{n\to\infty}\lim_{m\to\infty}\sqrt[n]{\frac{1}{m}}=\lim_{u\to\infty}\sqrt[u]{\frac{1}{u}}=1 Thanks
  47. Y

    Prove sq root of 2 + sq root of 3 is irrational

    hi,i read the post of sq root of 2 + sq root of 3.i understand tat i should use contradiction to solve it.yet,i stuck halfway when i tried to solve it. sq root 2 + sq root 3 = p/q 2 + 2*sq root 6 +3=p^2/q^2 5+2*sq root 6 = p^2/q^2 wat should i do after this?i hav to prove that the addition...
  48. G

    Finding the square root of a+bi (complex number)

    I was reading Roger Penrose' book "The Road to reality". He mentioned the square root of a+bi in terms of a and b. I am trying to figure his answer out for my self but am struggling. Here goes:(x+yi)^2=a+bi x^2+2xyi-y^2=a+bi x^2-y^2=a 2xy=b I can't rearrange these two equations to get x and...
  49. D

    Find the minimal polynomial with real root

    Find the minimal polynomial with root 21/3 + 21/2. I would just use maple but I do not have it installed on this machine. I found the polynomial and verified that this is indeed a root. I only have Eisenstiens criterion for determining whether it is irreducible, and I can not apply it in...
  50. T

    Square Root Problem: Solving for m in s=k√(1+m)/(1-m) | Help & Tips

    Homework Statement s=k\sqrt{\frac{1+m}{1-m}} , solve for m Homework Equations The Attempt at a Solution Honestly I am stumped, but I do know there is a trick to it. I can't quite remember, but it might have something to do with taking the reciperical or the inverse...maybe the...
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