Inverse Definition and 1000 Threads

  1. P

    Several matrix inverse properties

    Hi, I'm specifically trying to compute (VΔYT)-1, where V is nxn and orthogonal, Δ is diagonal, and Y is nonsingular. In general we have (AB)-1 = B-1A-1 But how do we do this in general for many matrices? Is there a method, and as long as the matrix dimensions agreed, does the...
  2. C

    Inverse of s(x)=[1+f(x)]/[1-f(x)]

    f is a one to one function with inverse f^-1, and we are asked to find the inverse of s(x)=[1+f(x)]/[1-f(x)] My attempts leave me with s^-1(x)= [f^-1(1-x)]/[f^-1(-x-1)] and I don't think this is correct. I can't find any examples of problems like this online.
  3. iVenky

    Why is Baye's theorem called inverse prob ?

    Why is Baye's theorem called "inverse prob"? What is the reason for calling Baye's theorem as "inverse probability"? Any valid reason? Thanks a lot
  4. M

    Inverse Fourier Transform and Power Signals

    I am having trouble with this homework problem, I know how to get started but I just don't know how to carry through the completion of the problem: Question: Given the Fourier transform of an aperiodic signal X(ω) = 2*sin(3(ω-2π))/ω-2π (a)find its inverse Fourier transform x(t) using...
  5. P

    Equation relating a function and its inverse

    so here's the question: if you have some equation relating a function, f(x), and its inverse, f-1(x), can you solve for the function? for example, solve for f(x): f(x)+f-1(x)=x^2 how about: f(x)+f-1(x)=g(x) my math teacher (AP calc) was stumped on this one... any thoughts?
  6. E

    How to Solve Inverse Laplace Transform: Factor or Use Complex Methods?

    I have to take the inverse laplace transform of the above function. Now, I know that I can factor (s^2+5s+6) as (s+3)(s+2) and take the easy way out. However, I did it as above on a test, getting A = -1, B = -1, and C = 1. I then took the inverse laplace transform and got something involving...
  7. H

    Finding inverse for a homeomorphism on the sphere (compactification)

    hi there I'd like to show that the sphere \mathbb{S}^n := \{ x \in \mathbb{R}^{n+1} : |x|=1 \} is the one-point-compactification of \mathbb{R}^n (*) After a lot of trying I got this function: f: \mathbb{S}^n \setminus \{(0,...,0,1)\} \rightarrow \mathbb{R}^n (x_1,...,x_{n+1})...
  8. B

    Is it possible for both AB and BA to be identity matrices if m does not equal n?

    Homework Statement Prove in general that if m does not equal n, then AB and BA cannot both be identity matrices, where A is mxn and B is nxm. Homework Equations None (that I know of at least). The Attempt at a Solution At first I thought it would be a good idea to define each...
  9. S

    INverse of a function between topological spaces and continuity

    Homework Statement Prove that if the inverse of a function between topological spaces maps base sets to base sets, then the function is continuous. Homework Equations The Attempt at a Solution I really don't know how to do this. Wikipedia entry for 'base sets' redirects to Pokemon...
  10. L

    Incorporating Inverse Square Law In Gravity

    First of all, I'm 13 so I might not comprehend the complex vocabulary or symbols others might use. Second, I just joined! Okay, let's get to it. I think I know what the inverse square law is: if a number goes up by x, then the other number is the square of x but in the negative side...
  11. P

    Simplfying Inverse Hyperbolic Cosine

    Homework Statement Simplify the following expression: arccosh \left(\frac{1}{\sqrt{1 - x^2}}\right) \forall x ∈ (-1, 1) Homework Equations cosh(u) = \left(\frac{1}{\sqrt{1 - tanh^{2}u}}\right) u ∈ ℝ The Attempt at a Solution x = tanhu ∴ u = arctanhx u ∈...
  12. W

    Inverse Laplace Transforms without Prefix

    Homework Statement find the partial fractions and thus the inverse of the following 6s^2-2s-11/(s-1)(s^2-1) and 7s^2+8s+16/(s+2)(s^2+3) Homework Equations answer tutor gave for the fist one was 3e^2t + 3cosht + sinht and second was 4e^-2t+3cos sqrt3t+ 2/sqrt3 sin sqrt3 The...
  13. matqkks

    MHB How can rotation matrices be used to motivate students?

    I am trying to find a real life inverse linear transform which can be used to motivate students. Does anyone have an example or two? I am looking for an example which will have a real impact. Thanks in advance.
  14. matqkks

    What Real Life Examples Exist for an Inverse Linear Transform?

    I am trying to find a real life inverse linear transform which can be used to motivate students. Does anyone have an example or two? I am looking for an example which will have a real impact. Thanks in advance.
  15. B

    Finding Inverse the Function of multiple variable functions

    I understand that given two functions f:X→Y and g:Y→X, to say that f is the inverse function of g means g o f:X→X is defined by g(f(x))=idx and to say g is the inverse function of f means f o g: Y→Y is defined by f(g(x))=idy I understand how to find inverses of one variable functions and...
  16. H

    Finding formula for the inverse of a function

    Homework Statement f(x)=e^x^2 f^(-1)(x)=? 2. The attempt at a solution i reversed x and y so i got x=e^y^2 ln both sides to get lnx=y^2 so (ln(y))^(1/2) what am i doing wrong?
  17. C

    Gradient of an inverse vector function?

    Homework Statement Consider f(\vec{x}) = |\vec{x}|^r, where \vec{x} \in ℝ^n and r \in ℝ. Find \vec{∇}f The Attempt at a Solution I know a vector function maps real numbers to a set of vectors, but here I believe we have the opposite. (inverse of a vector function, assuming inverse...
  18. E

    Does Doubling y in an Inverse Proportion Problem Halve the Constant?

    Hello if y \propto 1/x would 2y \propto 1/0.5x or 2y \propto 1/2x thank you for any replies
  19. 7

    4x4 lorentz matrix and finding its inverse

    I have been struggling to find an inverse to a Lorentz matrix \Lambda using formula: \Lambda^{-1}= \frac{1}{| \Lambda| }\textrm{adj}(\Lambda) from linear algebra. \Lambda = \begin{bmatrix} \gamma&0&0&-\beta \gamma \\ 0 & 1 & 0 & 0\\ 0 & 0 & 1 & 0\\ -\beta \gamma & 0 & 0 & \gamma...
  20. O

    MHB Finding the Inverse of Symmetric Matrices with Non-Real Coefficients

    Hello everyone! I'm struggling to find a general formula for obtaining an inverse of a symmetric matrix, for e.g. 1 i -1 i -i 2 -1 2 1 Any help is appreciated!
  21. T

    Inverse of Function: Topology by Munkres Ch 1

    I'm reading the first chapter of Topology by Munkres. There we can see: "if f is bijective, there exists a function from B to A called the inverse of f . (...) As another situation where care is needed, we note that it is not in general true that f^{-1}(f(A_0) = A_0 and...
  22. Y

    Help with inverse Laplace transform.

    I want to perform the inverse of \frac s { [(s+α)^2-β^2](s^2+ω^2)} I know the conventional way is \frac s { [(s+α)^2-β^2](s^2+ω^2)}= \frac{As+B}{[(s+α)^2-β^2]}+\frac{Ds+E}{(s^2+ω^2)} s= (As+B)(s^2+ω^2)+(Ds+E)[(s+α)^2-β^2] \Rightarrow\; A+D=0,\; B+E+2\alpha...
  23. C

    How Do You Invert the Function Q(t) in a Camera Flash Capacitor Model?

    Homework Statement When a camera flashes, the batteries begin recharging the flash capacitor which stores the charge Q according to the function Q(t) = Q* (1-e-t/a) where t is the elapsed time in seconds since the camera flash and Q* and a are non-zero (a) What does Q* represent? (b) Find the...
  24. R

    Inverse of matrix with unknown values

    Homework Statement Let B= \begin{pmatrix} λ-3 & 12 & -1 \\ 0 & λ+2 & λ \\ 0 & 0 & 5 \end{pmatrix} For what values of λ does matrix B have an inverse? Homework Equations The Attempt at a Solution I first tried to calculate det(B)=(λ-3)(5λ+10) +0 -0 to get x=-2 or...
  25. K

    How to write powers of inverse trigonometric functions?

    Does ##(\sin^{-1}\theta)^2 =\sin^{-2}\theta## ?
  26. A

    Finding the Inverse of a Function: Solving for y=x+√(x^2-1)

    Homework Statement I need to find the inverse of y=x+√(x^2-1) Homework Equations The Attempt at a Solution I know it's undefined from x=-1 and x=1 so there must be two different inverse functions on two different intervals. I don't know how to find them though.
  27. L

    Integration by u substitution for inverse trig formulas

    Homework Statement You know the U substitution proofs for inverse trig functions that go like this: \int\frac{1}{a^{2}+x^{2}}dx \int\frac{a\frac{1}{a}}{a(1+\frac{x^2}{a^2})}dx let u = x/a du= dx/a ... \frac{1}{a}tan^{-1}(x/a)+cI have searched google and can't find any of these proofs for...
  28. A

    How to write the algorithm? I have figured out a method to find the inverse.

    How to write the algorithm? I figured out a method to find the inverse. The assignment is making use of the property of triangular matrices to find the inverse of a matrix \displaystyle A. The inverse of a triangular matrix(Upper/ Lower) is also triangular(Upper/ Lower) and is easy to find...
  29. Y

    Finding the derivative of an unknowable inverse function

    Homework Statement The function f(x) has an inverse function, g(x). Find g'(5). Homework Equations f(x) = x^5 + 2x^2 + 2xThe Attempt at a Solution I don't see how I can possibly find the inverse of this function. So I opted to use the derivative rule for inverses. f'(x) = 5x^4 + 4x + 2 5...
  30. E

    Help with Inverse Fourier Transform Integral

    Hi, I am taking a random process class and I came across a problem that has stumped me. I believe I know the end result but I would like to know how it is solved. I have been out of college for a while and I am a little rusty with integration. Homework Statement What I need is to find out...
  31. C

    Definition of additive inverse and operation of negation.

    Hello everyone. I am slightly confused by these ideas so i would like your help. How is additive inverse defined? Is unary negation an operation in its own right just like those more familiar, like addition, multiplication? Or something else?
  32. W

    Trigonomic algebra to find the inverse of a relative mercator projection

    Hi guys, my first post here. This isn't homework or anything, just a personal project. Homework Statement I need to find the inverse of the relative mercator equation. That is, given an origin latitude/longitude, find the current latitude/longitude from an x,y point. Because longitude is...
  33. C

    Inverse Function problem involving e^x

    Homework Statement Let g(x) = (e^x - e^-x)/2. Find g^-1(x) and show (by manual computation) that g(g^-1(x)) = x. Homework Equations g(x) = (e^x - e^-x)/2 The Attempt at a Solution I get the inverse = ln[ (2x + sqrt(4x^2 + 4) ) / 2 ] How do I proceed?
  34. P

    Fastest way to find inverse of 4x4 matrix?

    What is the fastest way to find the inverse of a 4x4 matrix? The only way I know is to set up the matrix with the 4x4 matrix and the identity matrix and row reduce. But that takes forever sometimes.
  35. D

    How can I find the inverse equation for e^x/(e^x-1)?

    Homework Statement I'm having problems with finding the inverse equation for this function e^x/(e^x-1) The Attempt at a Solution Currently, I have done about 2 methods to solve it and hitting dead-ends on each one: Attempt 1. x=e^y/(e^y-1) then multiply both sides by (e^y-1) so...
  36. phosgene

    Derivatives of integrals and inverse functions

    Homework Statement Find the derivative of: 1. f(x)=arccos(5x^3) 2. f(x)=∫cos(5x)sin(5t)dt when the integral is from 0 to x Homework Equations Chain rule, dy/dx=dy/du*du/dx The Attempt at a Solution For the first one, I can just take 5x^3 as u and then apply the chain rule...
  37. FOIWATER

    Maple Maple issue - inverse laplace transform equation from a basic series RLC circuit

    maple issue -- inverse laplace transform equation from a basic series RLC circuit Pretty simple for some of you I know, but I have a laplace transform equation from a basic series RLC circuit ((sV-v(0))/L+si(0))/(s^2+sR/L+1/LC) = I(s) I want to take the inverse laplace of it, I am given all...
  38. S

    Inverse function of a quadratic and a cubic function?

    Homework Statement Homework Equations The Attempt at a Solution for 24. which is a quadratic function, i understand that you have to exchange the positions of x and y and solve from there...but my question is the inverse function of that quadratic for 24 is a negative number...
  39. H

    What Are the Inverse Images of Various Sets Under the Function f(x)=x^2?

    Homework Statement : Define f: ℝ→ℝ by f(x)=x^2. Find f^-1(T) for each of the following: (a) T = {9} (b) T = [4,9) (c) T = [-4,9] The attempt at a solution: So, the inverse of f should be f^-1(T)=+/-√(x). Therefor: (a) f^-1(9)= +/- 3 (b) f^-1(4)= +/- 2, f^-1(5)= +/- √(5), f^-1(6)= +/- √(6)...
  40. G

    How to rank random function from smallest to largest with inverse f included?

    Homework Statement The graph of y=f(x) is shown below. http://Newton.science.sfu.ca/cgi-bin/plot.png?file=public_public_1346904771_18810161_plot.data Rank the following from smallest(1) to largest(4). f−1(0) f(0) f(5) f−1(5) Homework Equations none available The...
  41. V

    Help with inverse trig functions

    Here is my problem: cot(arcsin(x)) my awnser: cot= x/(1-x)^1/2 The online program were suppose to use says I am wrong but I am not sure what I did wrong.
  42. L

    How to deal w/ inverse trig function within ∫(x)/((x^2-4)(√(x^4 -8)))?

    Evaluate the integral \int \frac{x}{(x^2 - 4) \sqrt{x^4 - 8x^2}} \, dx by making the substitution u = x^{2}Homework EquationsThe Attempt at a Solutionu = x^{2} - 4 so \frac{du}{2}= xdx \int \frac{1}{(x^2 - 4) \sqrt{x^4 - 8x^2}} \, xdx \frac{1}{2} \int \frac{1}{(u) \sqrt{x^4 - 8x^2}} \...
  43. H

    Recovering a function using the inverse fourier transform

    Homework Statement The argument of the kernel of the Fourier transform has a different sign for the forward and inverse transform. For a general function, show how the original function isn’t recovered upon inverse transformation if the sign of the argument is the same for both the forward and...
  44. S

    Inverse Square Law: 1mW laser range?

    Hello PF! I've got a strange question for you physics boffins; assuming for a moment that lasers obeyed the inverse square law, what range would a typical 1mW red laser have in the atmosphere?
  45. A

    Trigonometry Word Problem involving Inverse trigonometric functions

    Homework Statement A ship is d feet from a dock (horizontal distance). The dock is 40 feet above sea level. The angle of depression from the dock to the ship is θ. Write θ as a function of d. Homework Equations This question is accompanied with choices. The choices are (A) θ = 40arctan(d) (B)...
  46. A

    Finding x in an inverse trigonometric equation

    Homework Statement Given y = 2/3(arctan \frac{x}{4}), find x. Homework Equations Inverse trigonometric identities for tan. (I guess)The Attempt at a Solution I never attempted because it seems impossible for me. You think this is possible? Thank you!
  47. A

    Inverse Trigonometric Equation problem

    EDIT: 1.Homework Statement The problem asks to simplify this: cos(arcsin x)Homework Equations let arc sin x = θThe Attempt at a Solution EDIT: I have to edit because I received a warning for not posting for #3 and #2. I originally posted "cos(arcsin x)" for #2 because that was what I know...
  48. M

    Finding the inverse of a rational function

    Homework Statement Find the inverse of a rational function: f(x)=\frac{2x}{x-2} The Attempt at a Solution 1. Verify the function is one-to-one. Question: is there a way to do that withought drawing the graph? Some algebraic method? I know that this means that the function crosess any given...
  49. T

    Derivative of inverse function?

    Consider the function f: R-->R where F(x)= x, if x<1 x², if 1<x<9 (read x <or equal to 1 and x< or equal to 9) 27*sqrt(x), if x>9 I know that f is not differentiable at x=1 and x=9 because the derivative at each one of these points don't exist once the lateral limits don't coincide.(Is...
  50. C

    Exact Value of Inverse Trig Function

    Homework Statement How do I find out the exact value of tan^-1 (1 / sqrt(3))? Homework Equations nada The Attempt at a Solution I don't know where to start.
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