Recent content by CEL

  1. C

    Can anyone solve this mathematical induction problem?

    k is odd. So, k(n+1) is odd, no matter if (n+1) is odd or even. Since m is even, k(n+1) + m is odd.
  2. C

    Responses of a transfer function on MATLAB

    The response of a stable system to a ramp input is a ramp, so it tends to infinity. If you have a pole at the origin, the response to a ramp will be a parabola, as your graph shows.
  3. C

    Responses of a transfer function on MATLAB

    Your system has a pole at the origin. So, it is unstable. With a unit feedback it can be made stable, depending of the gain (your root locus graph).
  4. C

    Tension on a capacitor from Laplace domain to time domain.

    Your equation is dimensionally wrong! You wrote sV(s)-v(0). You have a voltage (v(0)) subtracted from the derivative of a voltage (sV(s)).
  5. C

    Factoring a 3rd order polynomial

    Try (w^4 - 59 w^2 + 630) + jw(14 - w^2) Then divide (w^4 - 59 w^2 + 630) by (14 - w^2)
  6. C

    Solving Non-Linear Systems with Higher Order Differential Equations

    An nth order differential equation can allways be represented as a set of n first order differential equations.
  7. C

    Are EMFs Really Causing Your Poor Sleep? Separating Fact From Fiction

    For a very good analysis of homeopathy, read http://depletedcranium.com/how-homeopathy-supposedly-works-illustrated/
  8. C

    Number of poles and rank of controllability matrix

    I agree with your answer. There are three observable and four controllable modes.
  9. C

    Test Stability using Routh Stability Method

    i + G(s)H(s) = 0 means: s^3+\alpha s^2 + 1 = 0 Since the polynomial is incomplete (there is no term in s^1) there is at least one root in the RHP and the system is unstable. No need to use Routh algorithm.
  10. C

    LastRatioBut I'm not sure if this is correct or not.

    the main error is in the statement: x(k)=x(k-2).*x(k-1); it should be: x(k)=x(k-2).+ x(k-1);
  11. C

    How Do You Apply Time Shift Properties in Laplace Transforms?

    In your work you made f(t-2) = t-2 so, f(t) = t and F(s) is the Laplace transform of t. F(s) = 1/s^2.
  12. C

    Producing Ramp Voltage Using Simulation: What You Need to Know

    You can use an integrator feeded by a step voltage.
  13. C

    Order & Poles: Basics of Control Engineering

    No, the order of the system is the number of poles (at the origin and elsewhere).
  14. C

    Engineering Solving a Circuit with Diodes: Find V Across Resistor

    Both diodes are forward biased. If they are ideal, you can replace them with short circuits. If not, you can replace them by voltage sources of 0.6 V.
  15. C

    How Does the 21-Card Trick Always Work?

    Remember, the column, where the chosen card is, is in the middle of the other two. When you lay the cards the second time, the cards that were formerly in the first column now constitute the first three cards of the first column and the first two cards of the other columns. The cards in the...