Euler Definition and 387 Threads

  1. J

    Conditions of the Euler Equation

    Hi everyone :D This is my problem: Find conditions on \alpha and \beta in the Euler equation x^{2}y'' + \alphaxy' + \betay = 0 such that: a) All solutions approach zero as x \rightarrow 0 b) All solutions are bounded as x \rightarrow 0 c) All solutions approach zero as x \rightarrow\infty I...
  2. M

    Can someone explain Euler angles?

    Can someone explain "Euler" angles? From what I read, "Euler" rotations are composed out of matrices like * * 0 1 0 0 * * 0 * * 0 0 * * * * 0 0 0 1 0 * * 0 0 1 which is pretty distinctive in that they rotate around same axis twice, and makes sense for devices like this...
  3. E

    What is the Proof of the Euler Lagrange Equation?

    [SOLVED] Euler Lagrange Equation Hi there , I am missing a crucial point on the proof of Euler Lagrange equation , here is my question : \frac{\partial f}{\partial y}-\frac{d}{dx}\left(\frac{df}{dy^{'}}\right)=0 (Euler-Lagrange equation) If the function "f" doesn't depend on x explicitly...
  4. C

    Betti numbers and euler characterstic?

    Let's say you have some type of simplicial complex that is made only of 2 simplices. What happens if all those 2 simplices are adjacent to a single edge (creating a type of book shape), so that this complex can only be embedded in dimensions 3+? Would this complex have the same 2nd betti number...
  5. H

    Translation of euler angles into rotation around arbitrary axis

    i have an orientation of a 3d object in space given by theeta, si and phi i.e. angles which the objects makes with respect to three axis. Now i want to translate the problem such that i get an arbitrary axis rotation about which to some calculated degrees would produce same orientation...
  6. E

    Solving the Euler Cauchy Equation: Finding the General Solution

    Homework Statement Find the general solution of x^2y" - 2y = 0 Homework Equations The Attempt at a Solution Can anyone tell me how to find the general solution of the Euler Cauchy equation. How do we make it into one?? Thanks.
  7. J

    Euler rotation of objects with velocity vectors

    I have a number of objects (points) in a 3D space. I need to rotate this space using euler angles (or equivilent) and place it in another coordinate system. (ie i start with objects placed within the confines of a cylinder aligned with the z axis, and after rotation have a cylinder of objects at...
  8. T

    Question on a form of the Euler constant

    I was wondering how I would go about proving this equation: \int_{1}^{\infty}\frac{u-[u]}{u^2}du=1-\gamma where \gamma is the Euler Constant, and [u] is the floor function
  9. S

    Usefulness of Euler line in triangles?

    Is the Euler line in triangles USEFUL for anything in real life? This is the line which contains the concurrency points for the intersections of the triangle perpendicular bisectors, the medians, the altitudes, but not the angle bisectors. Interesting stuff, but are these points which occur on...
  10. MathematicalPhysicist

    Calculate an integral using euler substituition.

    i was asked to calculate the integral: \int\frac{dx}{x+\sqrt{x^2-x+1}} by using euler substituition (i.e, finding a line which intersects sqrt(x^2-x+1) through one point and then the equation of the line will be y-y0=t(x-x0) where (x0,y0) is one point of intersection, and then substituing x for...
  11. O

    Why is the Euler Sum Infinite for Zeta=1?

    This may be a stupid question, but I do not understand why the Euler sum is infinite for zeta=1. Why is "1+1/2+1/3+1/4+... " infinite, but zeta=2 (1+1/4+1/9+...) not?
  12. K

    Graphing Euler Relationship as exponential spiral

    Hi everyone, I am trying to get an intuitive grasp of the Euler Relationship e^i(theta)=cos(theta)+i sin(theta) and also understand how to graph the exponential spiral, as demonstrated on this web page: http://www-math.mit.edu/daimp/ComplexExponential.html" Ok, first the neuron...
  13. D

    Proving Euler Equations and Solving Complex Numbers in Signal and Systems Course

    Hi i am reading about signal and systems course . What i want to prove is not a problem that i have to solve is something that the books take for granted and i want to prove it so i ll be able at exams to reprove so i won't have to remember it, (if u don't believe me i can give u the course's...
  14. quasar987

    The Klein bottle using the Euler caracteristic + orientability caracterisation

    I went off on my own to study the Euler caracteristic + orentability caracterisation of closed surface and I must have gotten lost somewhere, because I do not find that the Klein bottle is homeomorphic to \mathbb{R}P^2\#\mathbb{R}P^2 as I should. I started with the result that for two surfaces...
  15. B

    Differential equations - 2nd order euler eq'n

    (a) Let alpha (a) and beta (b) be given constant. show that t^r is a solution of the Euler equation t^2 d^2y/dt^2 + at dy/dt + by = 0 , t>0 if r^2 + (a-1)r + b = 0 (b) suppose that (a-t)^2 = 4b. Show that (ln t)t^(1-a)/2 is a second solution of Euler's equation. please help, i have no idea...
  16. Bob3141592

    Dr Euler and characteristic equations

    In "Dr. Euler's Fabulous Formula" by Paul Nahin, early in chapter 1 is discussed characteristic polynomials of a square matrix and the Cayley-Hamilton theorem, that any square matrix A satisfies its own characteristic equation. On page 21 it states p(lambda) = lambda^2 + a1*lambda + a2 = 0 and...
  17. D

    Results same w/ Euler, Improved Euler, & Runge-Kutta

    I've been trying to do some simulations using the Euler, improved Euler, and Runge-Kutta methods. My results for the improved Euler and Runge-Kutta are very close to my results with the plain old Euler method. If there is any improvement, it is negligible. This lack of improvement surprises...
  18. cepheid

    Solving Euler Integrals Homework: Show B(a,b)

    Homework Statement For fun: show that B(a,b) = \int_0^1{x^{a-1}(1-x)^{b-1}\,dx} = \frac{\Gamma(a)\Gamma(b)}{\Gamma(a+b)} where a > 0 , b > 0 . Hint: start from the product \Gamma(a)\Gamma(b) and switch to polar coordinates. The radial integral is proportional to \Gamma(a+b).Homework...
  19. G

    Euler was pronounced with a long u sound

    "Euler" was pronounced with a long "u" sound Ok, Up until last week I thought "Euler" was pronounced with a long "u" sound (like Euclid). Since most of the famous names of science/math are names I have read, not heard, I was wondering if someone could give me the correct pronunciation of...
  20. H_man

    MATLAB Is Matlab Suitable for Solving the Euler Equations in Fluid Dynamics?

    Hi, I was wondering if Matlab was the sort of program I'd want to solve the Euler Equations (fluid dynamics). And if it is, I am sure this must be a very standard problem.. does anybody know of any tutorials for this sort of problem as I have never used matlab? :-p
  21. B

    Proving the Divisibility of the Euler Function: A Number Theory Problem

    The Euler Function \varphi (n) is defined as the number of natural numbers less than n that are relatively prime to n. That is, \varphi (n) = | \{ a \in \mathbb{N} | a < n and gcd (a, n) = 1 \} | I have been asked to show that if a number d divides a number n, then \varphi (d) divides...
  22. K

    Vector rotation (possibly Euler angles)

    I'm looking for a method to rotate a 3D vector, and place it at an arbitary 3D point (x,y,z) without changing the vectors magnitude. I have briefly investigated eulers angles (mainly through wikipedia links etc), but don't fully understand the process yet. As an example, given the vector ...
  23. M

    What Are the Effects of the Euler Force?

    Can anyone describe what the effects of the Euler force are? If you're not familar with it, it is a fictitious force that arises from a rotating object undergoing a change in rotation speed. Can someone tell me what the effects of this fictitious force are?
  24. E

    Euler product and Goldbach conjecture

    In an anlaogy with the Euler product of the Riemann function we make: \prod_{p}(1+e^{-sp})=f(s) of course we have that: f(p1+p2+p3)=f(p1)f(p2)f(p3) f(x)=exp(-ax) if Goldbach Conjecture is true then p1+p2= even and p5+p6+p8=Odd for integer n>5? then this product should be equal to...
  25. A

    Where Is Earth's Nutation and Does the 23.5° Axial Tilt Ever Change?

    Hi, I would like to see the resemblance between planet Earth and a spherical top. I draw here the x-convention Euler angles as I know them: 24 hours to complete one complete one revolution around it's own z' axes. And the 23.5° Earth axes revolves around the "sun's z axes" - the line...
  26. V

    Proving Euler Line Parallel to Side BC in Triangle ABC

    Can anyone help me solve the following question. ABC is any triangle. XAB, YBC and ZAC are equilateral triangles formed on this triangle. Prove that AY, BZ and CX are concurrent. In a triangle ABC, the Euler line is parallel to side BC. Prove that tanB*tanC = 3. I just need a hint. I...
  27. M

    Solving Classic Euler Question on Buying Rice and Corn with 1770 Dollars

    Hi I'm told that the the following can be presented as a classic euler question: A farmer goes to marked with 1770 dollars to buy rice and corn. One bag of corn costs 10 dollars and one of rice cost 20 dollar. How much corn and rice can the farmer buy? This can be presented in the following...
  28. K

    Generating function for terms of Euler triangle?

    I'm sure this is relatively easy, but after an hour or so googling, I can't seem to find the formula for generating terms of the http://steiner.math.nthu.edu.tw/chuan/123/test/euler.htm Is this known by some other name? Maybe that's why I can't find it? Thanks
  29. D

    Please help me on calculating orbifold euler characteristics

    how could v 'calculate' the orbifold euler char. using String theorists' formula for the same ? For example, i know the Euler char. of S^1/Z_2 is 1, when we identify the x to -x points of S^1(not the antipodal points i.e. dimetrically opposite points, but putting a mirror along the horizontal...
  30. B

    Solving Euler Equation for X^m (m^2 + 1)^2 = 0

    I did solve this differential equation (x^4)y'''' + 6x^3y''' + 9x^2 + 3xy' + y = 0 using Cauchy Euler Equation. I got X^m (m^2 + 1)^2 = 0 I'm not sure how to get the roots of (m^2 + 1)^2. In my calculation I got m = -i, +i, -i, +i when I put m^2 = -1. In the book they have m = (+-)...
  31. M

    Euler Circuits and Vertices of Even Degree: Proof and Counter-Proof

    If a connected graph has a Euler circuit then this implies that all the vertices of the graph have even degree. Is the converse of this argument true? i.e. If a connected graph only contains vertices of even degree does this imply it contains an Euler Circuit? Could somebody please show me a...
  32. P

    Improving Euler's Approximation for Differential Equations: Tips and Resources

    Would you please tell me how to improve Euler's approximation to be better in solving differerential equations ? Can you give me some links to this? Thank you,
  33. honestrosewater

    Creating a Sequence Without Gauss: The Euler Challenge

    I think this will be my new mantra ;) but it is actually related to the question. I want to define the sequence (s_n) where n is natural and whose nth term, t_n, is the sum of the digits of n. I want to do this without using Gauss's modular arithmetic. This may be one of those 'easier said...
  34. S

    Euler' s equations and tau = zero?

    A uniform circular disk of mass m and radius a is constrained to rotate with constant angular speed omega abotu an axis making an angle theta with the disk' s axis of symmetry. Find the magnitude and direction of the angular momentum L and the torque tau exerted on the disk by its supporting...
  35. MathematicalPhysicist

    Taking the logarithm of the euler product

    can some one explain to me how is taking the logarithm of euler product gives you -sum(p)[log(1-p^s)]+log(s-1)=log[(s-1)z(s)]? my question is coming after encoutering this equation in this text in page number 2...
  36. G

    The Euler 9 Point Circle: Solving the Mystery of its Triangle Compatibility

    [SOLVED] Euler 9 point circle I'm doing a project on the nine point circle and i need to know what type of triangle it works with. I tried constructing it but it didn't work with an isoscoles or a obtuse triangle, but a website said it works with all triangles, can anyone help?
  37. J

    Solve Euler Integration for dx/dt = (x-at)/(x/a+t)

    Hi Im a bit stuck on the method for Euler Integration. I have the following first order differential equation: dx/dt = (x-at) / (x / a+t) where constant a = 1.0V/s, and initial condition x = 1.0V at t=0s I have a time step of 0.02 and I need to calculate the output voltage at a time...
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