Characteristic equation Definition and 30 Threads

  1. F

    Engineering Ordinary Diferential Equations in electric circuit

    It's a multiple choice exercise and I have managed to find the characteristic equation V0(t) which is ##V_0(t)= C_1e^{-t}+C_2e^{-3t}## Initially I thought that it was a non homogeneous ODE, but doing the math for the right part of the equation, I found out that it equals to 0. So, I need help...
  2. H

    Repeated roots of a characteristic equation of third order ODE

    The characteristic equation ## m^3 -6m^2 + 12m -8 = 0## has just one single, I mean all three are equal, root ##m=2##. So, one of the particular solution is ##y_1 = e^{2x}##. How can we find the other two? The technique ##y_2 = u(x) e^{2x}## doesn't seem to work, and even if it were to work how...
  3. W

    MHB Solving Matrix A: Characteristic Equation and Eigenvectors

    good evening everyone! Decided to solve the problems from last year's exams. I came across this example. Honestly, I didn't understand it. Who can help a young student? :) Find characteristic equation of the matrix A in the form of the polynomial of degree of 3 (you do not need to find...
  4. T

    Characteristic equation in terms of the Laplace operator

    Homework Statement The stability of a spinning body may be explored by using equation (3.40), with no torque components present. It will be assumed here that the spin is about the z -axis and has a rate ωZ = S. Homework Equations $$I_{xx}\dot{ω} - (I_{yy}-I_{zz})Sω_y = 0$$ $$I_{yy}\dot{y} -...
  5. K

    Characteristic equation with x^2 coefficient

    Homework Statement x2 d2y/dx2 + 3x dy/dx + 5y = g(x)Homework Equations How do we find Characteristic equation for it. The Attempt at a Solution x2λ2 + 3xλ + 5 = 0 λ1 = 1/2 [-x2 + √ (x4 + 20 ) ] λ2 = 1/2[ -x2 - √(x4 + 20) ] I used 1/3 -/+ a √(a2 + 4b) where a = x2 b = 5
  6. BiGyElLoWhAt

    Help with coefficients matrix in spring system

    Homework Statement The system is a spring with constant 3k hanging from a ceiling with a mass m attached to it, then attached to that mass another spring with constant 2k and another mass m attached to that. So spring -> mass -> spring ->mass. Find the normal modes and characteristic system...
  7. B

    Characteristic equation for recurrence equation

    An ODE of second order with constants coefficients, linear and homogeneous: Af''(x) + Bf'(x) +Cf(x) = 0 has how caractherisc equation this equation here: Ax^2 + Bx +C = 0 and has how solution this equation here: f(x) = a \exp(u x) + b \exp(v x) where u and v are the solutions (roots) of the...
  8. kostoglotov

    Question concerning 2nd order homogeneous linear diff eqs

    Homework Statement Regarding the case where the auxillary (characteristic) equation has complex roots, we solve the quadratic in the usual way using i to get the general solution y(x) = e^{\alpha x}\left(C_1 \cos{\beta x} + i C_2 \sin{\beta x}\right) And the textbook shows y(x) = e^{\alpha...
  9. H

    Linear Algebra: Characteristic Equation Factoring

    Homework Statement If I have the characteristic equation: -λ3 + 3λ2 + 9λ + 5 And I'm told that one of its eigenvalues is -1. How do I find the rest of the eigenvalues? Homework Equations -λ3 + 3λ2 + 9λ + 5 The Attempt at a Solution The furthest I can get is: -λ3 + 3λ2 + 9λ + 5 = (λ + 1) x...
  10. ognik

    Derive characteristic equation recursion relation

    Homework Statement Given an NxN symetric tri-diagonal matrix, derive the recursion relation for the characteristic polynomial Pn(λ) Homework Equations Pn(λ) = |A -λI | Pn(λ) = (An,n - λ)Pn-1(λ) - A2n,n-1Pn-2(λ) The Attempt at a Solution This was easy to do by induction, but I am always...
  11. R

    Differential equation/characteristic equation

    Any help is appreciated 1.)----Find the Character equation for the diff equation d^2y/dx^2-4dy/dx+3y=0 with initial conditions y(0)=0 and y'(0)=12 find the solution y(t) (this is what I have gotten so far on this part) p^2+4p+3=0 then (p-1)(p-3)=0 so p1=1 and p2=3? not really sure...
  12. D

    MHB Recovering PMF from characteristic equation

    I am integrating the characteristic equation in order to recover the PMF, but I am going to get the answer to be zero so something went wrong. \begin{align*} p_X[k]...
  13. C

    Show that r is repeated root for characteristic equation iff

    Homework Statement A:B→B a linear operator Show r is multiple root for minimal polynomial u(x) iff >$$\{0\}\subset \ker(A - rI) \subset \ker(A - rI)^2$$ note: it is proper subsetHomework Equations The Attempt at a Solution Homework Statement My thought: I know ker(A−rI) is basically {{0}...
  14. schrodingerscat11

    Getting the joint probability density for the characteristic equation

    Dear all, Greetings! I was given a problem from Reichl's Statistical Physics book. Thank you very much for taking time to read my post. Homework Statement The stochastic variables X and Y are independent and Gaussian distributed with first moment <x> = <y> = 0 and standard deviation...
  15. schrodingerscat11

    Getting the joint probability density for the characteristic equation

    Homework Statement The stochastic variables X and Y are independent and Gaussian distributed with first moment <x> = <y> = 0 and standard deviation σx = σy = 1. Find the characteristic function for the random variable Z = X2+Y2, and compute the moments <z>, <z2> and <z3>. Find the first 3...
  16. E

    The sign of terms in a characteristic equation of a PDE

    This was something I noticed as I was trying to practice solving PDEs using the method of characteristics. The text has the following example: $$\frac{\partial u}{\partial x} + x \frac{\partial u}{\partial y} = 0$$ This should be easy enough. I let p(x,y) = x and solve for \frac{\partial...
  17. H

    IV characteristic equation of triple junction solar cell

    Homework Statement The given quantities are the shunt resistances across each of the 3 diode junctions,assume them to be Rsh1,Rsh2,Rsh3; Tunnel diode resistances as Rt1 and Rt2, Photocurrent for each of the junction be Ip1,Ip2,Ip3 and bandgap of each subcell be Eg1,Eg2,Eg3 are given.Let V & I...
  18. A

    Complex root for characteristic equation

    Suppose your characteristic equation for the 2nd order equation has complex roots r+ and r- These are conjuagtes of each other so the general solution is: y = Aer+ + Ber- My book chooses the constants A and B as conjugates of each other for the reason that this constructs a real...
  19. Z

    2nd order characteristic equation standart form

    A second order system has the following standart form; http://controls-design.com/mathtex/mathtex.cgi?H%28s%29%3DK%5Cfrac%7B%5Comega_n%5E2%7D%7Bs%5E2%2B2%5Czeta%5Comega_n%20s%2B%5Comega_n%5E2%7D%20%5Cmbox%7B%20for%20%7D%200%20%5Cle%20%5Czeta%20%5Cle%201 However, sometimes the system I...
  20. S

    Characteristic equation formula for a nxn matrix ?

    So I know that the characteristic equation for a 2x2 matrix can be given by t^2 - traceA + |A| So how would this be generalised for a 4x4 or higher matrix ?
  21. S

    Coefficients of the characteristic equation

    let's say you are given the following matrix T: T11 T12 . . . T1n T21 T22 . . . T2n . . . . . . . ...
  22. N

    Solving Characteristic Equation: y'''-y''+y'-y=0

    I am stuck on solving for the roots of a charactristic equation: y'''- y''+y'-y=0 where I set r^3-r^2+r-1=0 and factored out r to get r*[ r^2-r +1] -1 =0 to get the real root of 1. How can I solve for the compex roots?
  23. S

    Characteristic equation of binomial random variable

    Homework Statement find the characteristic equation of a binomial variable with pmf p(x) =\frac{n!}{(n-k)!k!}*p^{k}*(1-p)^{n-k}Homework Equations characteristic equation I(t) = \sump(x)*e^{tk}The Attempt at a Solution I(t) = \sum\frac{n!}{(n-k)!k!}*(p^{k}*(1-p)^{-k}*e^{tk})*(1-p)^{n} i am...
  24. Gspace

    HELP Characteristic Equation question

    Homework Statement Come up with the frequency directly from the solutions of the characteristic equation. {{z=0.-5.71839 i},{z=0.+5.71839 i}} Homework Equations characteristic equation = z^2+b z+c=0 The Attempt at a Solution Not sure where to start. Any help would be greatly...
  25. C

    A question about the characteristic equation

    Hi PF readers, When trying to establish \lambda values by solving a characteristic equation (for simplicity of 2x2 matrix) can one produce solution that contains complex roots? If yes, what does that show about the eigenvectors? Thanks in advance! Cygni
  26. E

    Matlab - ODE, find roots of the characteristic equation for the natural response

    Homework Statement I need to use MATLAB to solve these problems. http://users.bigpond.net.au/exidez/IVDP.jpg Homework Equations MATLAB The Attempt at a Solution a) R1=3.6; R2=R1; C1=33*10^-6; C2=22*10^-6; % defining the polynomial constants Vs=[R1*R2*C1*C2...
  27. R

    Characteristic Equation for Asin(Wt) + Bcos(Wt): Explained

    http://users.on.net/~rohanlal/qM.jpg I don't understand how this answer is obtained for the homogenous solution. What does characteristic equation in "r" mean and how does it help achieve the final solution of Asin(Wt) + Bcos(Wt)?
  28. R

    What Is the Characteristic Equation of the ODE x''+2x'+6x=sin2t?

    For the ODE x''+2x'+6x=sin2t what is the characteristic equation? Is it m^2+2m+6=0 or m^2+2m+6=cos2t
  29. L

    Characteristic Equation for Parallel Circuit with Current Source and 3 Elements

    Homework Statement im trying to find the characteristic equation of a circuit with a current source and 3 elements all in parallel: a resistor and 2 inductors L1 and L2. Homework Equations i believe the current can be calculated as: i(t) = v(t)/R + iL1(t) + iL2(t) The Attempt at a...
  30. C

    Why Do We Get the Same Characteristic Equation for DEQs and Matrix A?

    Let's say I'm given a DEQ: (1) y^{(n)}+a_{n-1}\cdot y^{(n-1)}+\ldots + a_{0}\cdot y=0, where y is a real function of the real variable t, for example. I could now rewrite this as a system of DEQ in matrix form (let's not discuss why I would do that): (2) x'=Ax,\quad x=(y,\ldots,y^{(n-1)}). If I...
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