Recent content by CentreShifter

  1. C

    Expressing time-dependent ODE

    Excellent. Thank you.
  2. C

    Expressing time-dependent ODE

    This is surely the simplest problem imaginable in DE, but it's been a few years and I'm having trouble recalling. The goal of my task doesn't necessitate relearning DE, so I thought I would take a shot at asking directly. Simply, I wish to express the time-dependent rate equation...
  3. C

    Calculating the direction of magnetic field at a point above a loop of current

    I've uploaded my attempted solution here. The problem I'm having is highlighted at the bottom in red. The issue I'm having is expressing the direction of H. I realize the cancellation that occurs at point (0,0,z), where the only the z-component of the H-field remains. I also realize that my...
  4. C

    Efficient Boolean Minimization Techniques: Simplifying Y = \bar{X}_1+\bar{X}_0

    This is just a general question regarding Boolean minimization. Expression: Y=\bar{X}_1\bar{X}_0+\bar{X}_1X_0+X_1\bar{X}_0 Minimized expression: Y=\bar{X}_1+\bar{X}_0 My first attempt was to minimize it algebraically. I factored \bar{X}_1 from the first two terms, then the \bar{X}_0+X_0...
  5. C

    [Linear Algebra] Showing equality via determinant properties

    Problem: Show, without evaluating directly, that \left|\begin{matrix} a_1+b_1t&a_2+b_2t&a_3+b_3t \\ a_1t+b_1&a_2t+b_2&a_3t+b_3 \\ c_1&c_2&c_3 \end{matrix}\right| = (1-t^2)\left|\begin{matrix} a_1&a_2&a_3 \\ b_1&b_2&b_3 \\ c_1&c_2&c_3 \end{matrix}\right| Clearly, here I'm...
  6. C

    Finding the Inverse of a Sum of Matrices: A Step-by-Step Guide

    Beautiful. Inverting both sides did the trick. Inverse of the RHS is \begin{bmatrix}\frac{-5}{13} & \frac{2}{13} \\ \frac{4}{13} & \frac{1}{13} \end{bmatrix}. I'll call this B^{-1} So then I'm left with \begin{align}I+2A&=B^{-1} \\ 2A&=B^{-1}-I \\...
  7. C

    Finding the Inverse of a Sum of Matrices: A Step-by-Step Guide

    Inverse of a sum of matrices [solved] The problem is relatively simple. Given the equation: (I+2A)^{-1}= \begin{bmatrix} -1 & 2 \\ 4 & 5 \end{bmatrix} Find A. My problem seems to be that I'm distributing the inverse on the LHS incorrectly. My real question then is, is the...
  8. C

    Problem solving equation with negative exponent

    It isn't real. This was one part of a practice problem I was solving as to lead me up to DEs, which I need to reacquaint myself with.
  9. C

    Problem solving equation with negative exponent

    Thanks to all who responded. I believe I was doing my computations incorrectly. I am given voltage: 100e^{-500t}V And current: 20-20e^{-500t}mA Power being the product: 2e^{-1000t}(e^{500t}-1)W And derivative: -1000e^{-1000t}(e^{500t}-2) To find out when power is...
  10. C

    Problem solving equation with negative exponent

    I'm trying to calculate maximum power. Once I computed power as a function of time I took its derivative and set it equal to zero. Now it need to solve for time and I can't seem to get it done. What I have is... -1000e^{-500t}-2000e^{-1000t}=0 My first inclination is to use ln, but ln(0)...
  11. C

    How do I solve for t using the Laws of Logs in this algebraic equation?

    I need to solve for t and it's slipped my mind how to manipulate this. \frac{1}{4}=te^{-8t} to ln(1/4)=lnt-8t I understand the laws of logs (I think), but I still can't seem to isolate the t.
  12. C

    Determination of Unknown Constants in Differential Equations

    From what I understand you are correct, an equation with n derivatives requires n initial conditions. Not too sure if the same applies for coupled DEs though.
  13. C

    Solving EXACT Equations: A Step-by-Step Guide

    In order to determine what the integrating factor is you must first normalize the equation. \frac{dy}{dx}+P(x)y=f(x) is an example of a normalized differential equation, the IF being e^{\int P(x)dx}. Does this help?
  14. C

    Can someone verify my solution?

    You are both absolutely correct. I was the end of my study session, there should definitely be an equation there. I'll be posting it as soon as I can get to the book. @arildno - I know this doesn't help right now, but the problem is to be solved using Laplace transforms, not undetermined...
Back
Top