Inverse Definition and 1000 Threads

  1. M

    Tricky inverse Laplace transform

    << Moderator Note -- thread moved to the Homework Help forums >> I'm stuck on a problem, and I'm in serious need of help. I) Problem: Find the solution to f (t) = 2 \int^t_0 f'(u) sin 3 (t-u) \ du + 2 cos (3t) . Also find f (0) .II) Solution, so far: F(s) = 2 (s F(s) - f(0)) *...
  2. kewei chen

    Inverse Laplace transform with p^-1 and exponential

    Hello everyone, I have spend whole day but still not figure out an inverse Laplace transform. Hope someone can help me. The question is in the attachment. I'm trying to extract u^2/4D^2 out the bracket to match the standard inverse table, but it seems difficult to deal with the square root...
  3. 462chevelle

    Solve Inverse Functions: Find (f^-1)'(a) for f(x)=Cos(2x), a=1

    Homework Statement Verify that f has an inverse <- prof told us not to worry about this. Then use the function f and the given real number a to find (f^-1)'(a). f(x) = Cos(2x), 0<=x<=pi/2 where a=1 Homework Equations 1/(f'(g(x))) where g(x)=f^-1(a) d/dx(cos(2x)) = -2sin(2x) The Attempt at a...
  4. I

    Inverse matrix word problem, matrix arithmetic

    Homework Statement Hello! Please, take a look at the attached picture - there is a quote of the exercise and below is my attempt to make a matrix. Is my matrix correct? I have tried many times to convert it to inverse one, but I can't figure out how to do it - I keep getting "inconvenient"...
  5. ellipsis

    No Inverse for sin(x)+x Function

    The normal answer is "no, there is no inverse function in terms of the normal operators and trigonometric functions." That is to say, given a value of x, you cannot find the value of y of the input function reflected over the x-y axis using standard functions. "Standard functions" is what is...
  6. S

    Does the inverse of this special matrix have a power series expansion?

    Hi...can anyone please suggest whether the following inverse has a power series expansion (I+\delta A)^{-1} where \delta is a constant and A = \begin{pmatrix} T & T-1 & T-2 &... & 3 & 2 & 1\\ T-1 & T-1 & T-2 & ... & 3 & 2 & 1 \\ .. \\2 & 2 & 2 &... & 2 & 2 & 1 \\ 1 & 1 & 1 & ... & 1 & 1 & 1...
  7. P

    Transpose Inverse Property (Dual Vectors)

    Hello, While studying dual vectors in general relativity, it was written as we all know that dual vectors (under Lorentz Transformation) transform as follows: \tilde{u}_{a} = \Lambda^{b}_{a}μ_{b} where \Lambda^{b}_{a}= η_{ac}L^{c}_{d}η^{db} I was wondering if one can prove the latter...
  8. C

    Beta decay and inverse beta decay is different?

    So in beta decay I know a neutron can decay into, proton, electron and antineutrino (Or, neutrino, since they're both the same?) But anyhow, regardless of the neutrino, in neutron stars electron degeneracy doesn't hold and electrons combine with photons to form neutrons. But isn't that...
  9. M

    Inverse laplace transform (polynomial division? Complex roots?)

    Homework Statement Decide the inverse laplace transform of the problem below: F(s)= \frac{4s-5}{s^2-4s+8} You're allowed to use s shifting. Homework Equations The Attempt at a Solution By looking at the denominator, I see that it might be factorized easily, so I try that...
  10. Q

    Inverse Laplace transform where e^(st)F(s) is entire

    Heya folks, I'm currently pondering how to decide whether a function has an inverse Laplace transform or not. In particular I am considering the function e^(-is), which I am pretty sure does not have an inverse Laplace transform. My reasoning is that when calculating the inverse by the Bromwich...
  11. M

    Original function with inverse

    Homework Statement Can an inverse function be determined as either even or odd simply given its original function?
  12. M

    Proving each nonzero element of a subfield of C has an inverse

    Homework Statement Let S={p+qα+rα2 : p, q, r \in \mathbb{Q}}, where α=\sqrt[3]{2}. Then S is a subfield of \mathbb{C}. Prove that each nonzero element of S has a multiplicative inverse in S. The Attempt at a Solution Let p, q, r\in\mathbb{Q} such that not all of p, q, r are zero. If...
  13. M

    So the inverse transform of \frac{3s+ 5}{s^2+ 9} is 3cos(3x)+ (5/3)sin(3x).

    Homework Statement Find the inverse Laplace transform of the expression: F(S) = \frac{3s+5}{s^2 +9} Homework Equations The Attempt at a Solution From general Laplace transforms, I see a pattern with laplace transforming sin(t) and cos(t) because: L{sin(t)+cos(t)} =...
  14. W

    Formula of an inverse function

    Homework Statement Find the formula of the inverse function of f(x)=300/(3+15e^.05x). Homework Equations f(x)=300/(3+15e^.05x) The Attempt at a Solution I'm definitely way off but I got .05y(5x)+ln100=lnx. What I did was multiple the denominator by the y(cross mltiplication)...
  15. C

    MHB Generating an inverse function from the given one

    Hi, I have a relationship $$P \cong \Bigg[\Big(K_1\rho^{\frac{5}{3}}\Big)^{-2}+ \Big(K_2\rho^{\frac{4}{3}}\Big)^{-2}\Bigg]^{-\frac{1}{2}}$$I need to find the inverse as $$\rho= \rho(P)$$. I made a detailed calculation and came up to this $$y^5+\Big(\frac{P}{K_2}\Big)^2 y+...
  16. DavideGenoa

    Banach's inverse operator theorem

    Dear friends, I have been trying in vain for a long time to understand the proof given in Kolmogorov and Fomin's of Banach's theorem of the inverse operator. At p. 230 it is said that M_N is dense in P_0 because M_n is dense in P. I am only able to see the proof that (P\cap M_n)-y_0 \subset...
  17. A

    What is the Inverse Function of g(x)?

    Consider the function g(x) represented by the table below: x -6 -4 -2 0 2 4 6 g(x) -4 -2 4 0 6 -6 2 Complete the table of values for the INVERSE, g^{-1}(x), in the table below: x -6 -4 -2 0 2 4 6 g^{-1}(x)
  18. S

    Finding Inverse of Matrix by using Gaussian-Jordan Elimination

    Hello. Nice to meet you. I have just enrolled. :) I knew how to solve and to find out inverse Matrix by using Gaussian elimination. However, I was wondering why AI -> IA' is satisfactory. In my university, I was just taught how to use but wasn't taught why it is satisfactory. Thank you for...
  19. B

    GR: Metric, Inverse Metric, Affine Connection Caluculation Help

    Homework Statement Consider the Schwarschield Metric in four dimensional spacetime (M is a constant): ds2 = -(1-(2M/r))dt2 + dr2/(1-(2M/r)) + r2(dθ2 + sin2(θ)dø2) a.) Write down the non zero components of the metric tensor, and find the inverse metric tensor. b.) find all the...
  20. A

    Oscillations and inverse square law

    Homework Statement A particle of mass m moves in 1 dimension along positive x direction.It is acted on by a constant force directed towards origin with magnitude B,and an inverse square law repulsive force with magnitude A/x^2.Find equilibrium position. Homework Equations B+A/x^2=m*a...
  21. Dethrone

    MHB Domain and range of inverse functions (circular and hyperbolic)

    I've always been having trouble with the domain and range of inverse trigonometric functions. For example, let's start with an easy one: $\sin^{-1}\left({x}\right)$ Process: First, I draw out the function of $\sin\left({x}\right)$. Then I look at its range and attempt to restrict it so that it...
  22. F

    Find Value of arccot(pi/4): Explanation & Solution

    Homework Statement Fin the value of arccot(pi/4) Homework Equations unit circle The Attempt at a Solution I honestly can't believe that I'm stuck on this as this shouldn't stump me. My logic is that since its inverse cotangent then its related to inverse tangent and so the...
  23. R

    Dimensional Analysis: Inverse Cosine

    Homework Statement For the following dimensional equation, find the base dimensions of the parameter f: M M-3 = a cos( f L ) Homework Equations M represents mass, a represents acceleration due to gravity, in terms of mass * length over seconds squared [[M * L]/[t2]] where L represents length...
  24. N

    Indoor Flower Garden & Plant Growth: Inverse Square Law

    Hi all looking for a bit of advice me the misses and the kids are starting a indoor flower garden and some herbs for the kids now my problems have come down to the lighting I have found out the colour spectrums needed as well as the luminous intensity required for heathly plant growth but the...
  25. M

    Divergence of an inverse square field

    Reference to Griffith electrodynamics question:- 1.16 Compute the divergence of an inverse square vector field. Now gradient is (∂/∂r)(r cap) Hence upon taking divergence of inverse square field (r cap)/r^2...We don't get 0. In fact we get (-2)/r^3. But if we write the vector field and...
  26. Y

    MHB Inverse of adjoint - where is my mistake ?

    Hello all, I have a matrix A: \[\begin{pmatrix} 2 &4 &1 \\ -4 &7 &3 \\ 5 &1 &-2 \end{pmatrix}\] and I need to find the adjoint of the matrix inverse. I found adj(A) to be: \[\begin{pmatrix} -17 &9 &5 \\ 7 &-9 &-10 \\ -39 &18 &30 \end{pmatrix}\] and I found the determinant of A to be -45 and...
  27. anemone

    MHB Find Integer $k$ to Satisfy Sum of Inverse Progression > 2000

    Find an integer $k$ for which $\dfrac{1}{k}+\dfrac{1}{k+1}+\dfrac{1}{k+2}+\cdots+\dfrac{1}{k^2}>2000$.
  28. N

    Help please -- inverse Laplace transform of 1/(x^2+1)^2

    Homework Statement Hi. I need help to resolve the inverse laplace transform of {1/((x^2)+1)^2}2. The attempt at a solution I have tried to do: {(1/((x^2)+1) * (1/((x^2)+1)} then, convolution, sen x But, isn't working Thanks for your help :)
  29. O

    Calculating Inverse z-Transform for X(z) = z/(z-0.2)^2(z+0.1)

    Homework Statement Find inverse z-transform of X(z) = \frac{z}{(z-0.2)^2(z+0.1)} Homework Equations The Attempt at a Solution : partial fraction My method :\frac{X(z)}{z} = \frac{1}{(z-0.2)^2(z+0.1)} \frac{X(z)}{z} = \frac{-100/9}{(z-0.2)} + \frac{10/3}{(z-0.2)^2} + \frac{100/9}{z+0.1} X(z) =...
  30. A

    MHB Derivatives and Inverse Trigonometry

    Hey guys, I have a couple of questions about this problem set I've been working on. I'm doubting some of my answers and I'd appreciate some help. Question: For 1a, using inverse trigonometric derivative identities should work, right? I got y' = 1/sinØ + 1/cosØ and multiplied by the common...
  31. A

    MHB What is the Domain for the Inverse of a One-to-One Function?

    Hey guys, I've a few more questions this time around from my problem set: (Ignore question 2abc, I only need help with the first one) Question: For the first one, in order to prove that a function is one-to-one, f(x1) =/ f(x2) when x1 =/ x2. Thus, the horizontal test applies. So I said...
  32. A

    MHB Inverse Functions and "Verifying"

    Hey guys, I have a couple more questions about this problem set I've been working on. I'm doubting some of my answers and I'd appreciate some help. Question: Alright, I'm having quite a bit of trouble with these. So here it goes: For the first one, I did the 3-step procedure to finding the...
  33. Mogarrr

    Is the Inverse Calculation for a Piecewise CDF Correct?

    Homework Statement Show that the given function is a cdf (cumulative distribution function) and find F_X^{-1}(y) (c) F_X(x) = \frac {e^{x}}4 , if x<0, and 1-(\frac {e^{-x}}4) , if x \geq 0 Homework Equations for a strictly increasing cdf, F_X^{-1}(y) = x \iff F_X(x) = y and for a...
  34. K

    How to Find the Inverse Laplace Transform for Ds + E / (s^2 +1)^2?

    Homework Statement Ds + E / (s^2 +1)^2 Homework Equations The Attempt at a Solution Ds / (s^2 +1) + E / (s^2 +1) D[s/(s^2 + 1)^2] + E [1 / (s^2 + 1)^2]
  35. D

    MHB Simplifying the inverse Laplace Transform using the inverse shift formula

    before I go to bed(it's 11:30pm in my place), here is the last problem that I need help with find the inverse Laplace Transform $\frac{4s-2}{s^2-6s+18}$ the denominator is a non-factorable quadratic. I don't know what to do. thanks!
  36. D

    MHB Inverse laplace transform of a function

    find the inverse Laplace of the ff: 1. $\frac{n\pi L}{L^2s^2+n^2 \pi^{2}}$ 2. $\frac{18s-12}{9s^2-1}$ for the 2nd prob I did partial fractions $\frac{18s-12}{9s^2-1}=\frac{9}{3s+1}-\frac{3}{3s-1}$ $\mathscr{L}^{-1}\{\frac{18s-12}{9s^2-1}\} =...
  37. vyas22

    Is There a Maximum Distance Limit in Our Universe?

    Hello all, If Planck length (1.61619926 × 10(-35 )meters) places a theoretical limit on minimum possible distance does it also imply that we have a maximum theoretical limit on measurable length as inverse of Planck length (1/Planck Length).. does there any such limit on the maximum...
  38. D

    What is the inverse of the 3x3 matrix mod 26

    Homework Statement What is the inverse of the 3x3 matrix mod 26? K = \begin{pmatrix} 17 & 17 & 5\\ 21 & 18 & 21\\ 2 & 2 & 19 \end{pmatrix} Homework Equations The Attempt at a Solution So I found all the cofactors and then took the transpose of the matrix. I then...
  39. D

    How Do You Find the Inverse of a Matrix Modulo 26?

    Homework Statement \begin{pmatrix} 5 & 8\\ 17 & 3\\ \end{pmatrix} The matrix given above is matrix A and I am trying to find A-1 mod 26 = ?Homework Equations ax+by = cThe Attempt at a Solution Well first I found the det of A which is -121 and then took -121 modulus of 26 which gave me 9. Did...
  40. bsmithysmith

    MHB Continuity of the Inverse Function

    I just started Calculus 1, a summer quarter that's compressed and I'm having trouble understanding a theorem that state continuity of the inverse function. Within my textbook, it mentions "If f(x) is continuous on an interval I with range R, and if inverse f(x) exists, then the inverse f(x) is...
  41. PsychonautQQ

    Finding the Inverse Integer Modulo n

    Homework Statement in mod 35, find the inverse of 13 and use it to solve 13x = 9 gcd(35,13) =1 so the inverse exsists: 35 = 2*13 + 9 13 = 1*9 + 4 9 = 2*4 + 1 4 = 4*1 and then to find the linear combination 1 = 9 - (2*4) = 9 - 2(13-9) = 3*9 - 2*13 = 3* (35 - 2*13) - 2*13 = 3*35 - 8*13 =...
  42. A

    Why is the matrix $(A^{-1}+B^{-1})$ not equal to $(A+B)^{-1}$?

    Show that if A, B and A+B are invertible matrices with the same size, then $$A(A^{-1}+B^{-1})B(A+B)^{-1}=I$$ What does the result in the first part tell you about the matrix $$(A^{-1}+B^{-1})$$? I get the first part. Help me with the second part. My book says that the matrix...
  43. J

    RLC changes negatively when is measured in the inverse sense?

    If ##V_{BA} = P_B - P_A## (where V is the voltage and P the potential) so, ##V_{AB} = - V_{BA}##. The same ideia for the current: ##i_{BA} = - i_{AB}##, so this ideia of sense is true too for resistor, inductor and capacitor? The resistance, inductance and capacitance of an arbitrary sense is...
  44. P

    MHB Muhammed's question via email about an Inverse Fourier Transform (2)

    Here we will use the following transforms: $\displaystyle \begin{align*} \mathcal{F}^{-1} \left\{ \frac{n!}{ \left( a + \mathrm{i}\,\omega \right) ^{n+1} } \right\} = t^n\,\mathrm{e}^{-a\,t}\,\mathrm{H}(t) \end{align*}$ and $\displaystyle \begin{align*} \mathcal{F}^{-1} \left\{...
  45. P

    MHB Muhammad's question via email about an Inverse Fourier Transform

    Completing the square gives $\displaystyle \begin{align*} \frac{2\mathrm{i}\,\omega}{\omega ^2 + 10\omega + 29} &= \frac{2\mathrm{i}\,\omega}{ \omega ^2 + 10\omega + 5^2 - 5^2 + 29} \\ &= \frac{2\mathrm{i}\,\omega}{ \left( \omega + 5 \right) ^2 + 4 } \\ &= \frac{2\mathrm{i}\,\omega}{ \left(...
  46. Mandelbroth

    Category Theory: Inverse Limit in Sets

    I think this looks like a homework problem, so I'll just put it here. Homework Statement Demonstrate that, for any index category ##\mathscr{J}## and any diagram ##\mathcal{F}:\mathscr{J}\to\mathbf{Sets}##, $$\varprojlim_{\mathscr{J}}A_j=\left\{a\in \prod_{j\in \operatorname{obj}(...
  47. E

    The inverse of a banded matrix

    Hello all, I have say 512-by-512 matrix, but based on the structure of this matrix most elements not on the diagonals between -5 to +5 (- stand for diagonal below the main diagonal, and + for diagonal above the main diagonal) are small relative to the elements of the mentioned diagonals. So...
  48. J

    MHB Evaluation of Infinite sum of Inverse Trig. Series.

    How can we prove $$\displaystyle \tan^{-1}\left(\frac{4}{7}\right)+\tan^{-1}\left(\frac{4}{19}\right)+\tan^{-1}\left(\frac{4}{39}\right)+\tan^{-1}\left(\frac{4}{67}\right)+...\infty = \frac{\pi}{4}+\cot^{-1}(3)$$ My Trial: First we will calculate $\bf{n^{th}}$ terms of Given Series...
  49. DreamWeaver

    MHB How Do You Solve the Inverse Tangential Integral with Scalar Constants?

    For the scalar constants \{a, \, b, \, c,\, d, \, z\} \in \mathbb{R}, and 0<z<1, find the most general solutions of the parametric integral \int_0^z\frac{\tan^{-1}(ax+b)}{(cx+d)}\, dxand the restrictions on \{a, \, b, \, c, \, d\} that satisfy such general solutions.Go on... You know you want...
  50. J

    Inverse Fourier Transform of |k|^2$\lambda$

    Homework Statement \int_{-\infty}^{\infty} |k|^{2\lambda} e^{ikx} dkHomework Equations The Attempt at a Solution As you can guess, this is the inverse Fourier transform of |k|^{2\lambda}. I've tried splitting it from -infinity to 0 and 0 to infinity. I've tried noting that |k| is even, cos is...
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