Courses

1. Linear Algebra
2. Multivariable Calculus
3. Differential Equations
4. Miscellaneous Topics

Differential Equations

1. Introduction
   1. Notation and Definitions
   2. Verifying Solutions
   3. Initial Values Problems
2. First Order Differential Equations
   1. Direction Fields
   2. Equilibria, Stability, and Phase Lines
   3. Separable Equations
   4. Integrating Factor
   5. Bernoulli Equations and Substitutions
   6. Exact Equations
   7. Exact Equations with Integrating Factor
   8. Euler's Method
   9. Existence and Uniqueness
   10. Interval of Validity
   11. Applications
       1. Radioactive Decay and Population Growth
       2. Mixing Tank Problem
       3. Terminal Velocity
       4. Continuous Compound Interest
3. Wrońskian
4. Second Order Differential Equations
   1. $ay''+by'+cy = 0$
      1. Distinct Real Roots
      2. Repeated Real Root
      3. Imaginary Roots
   2. Spring-Mass-Damper
      1. Equivalent RLC Circuit
      2. Underdamped, Overdamped, Critically Damped
      3. Undamped Oscillations and Resonance
   3. Method of Undetermined Coefficients
   4. Reduction of Order
   5. Variation of Parameters
   6. Cauchy-Euler Equations
5. Laplace Transform
   1. Lookup Table and WolframAlpha
6. Systems of ODEs
   1. Simplest Case $\begin{bmatrix}x' \\ y'\end{bmatrix} = \begin{bmatrix}a & b \\ c & d \end{bmatrix}\begin{bmatrix}x \\ y\end{bmatrix}$
      1. Poincaré Diagram
7. Preview of Dynamical Systems
   1. Self-Study
   2. Rössler Attractor

Additional Resources

1. WolframAlpha Examples
2. Direction Field Plotter by Ariel Barton
3. Phase Plane Plotter by Ariel Barton

Undamped Oscillations and Resonance | Topic Playlist

Resonance in a mechanical system, such as a mass-spring-damper system, is when an oscillating force being applied to the system causes a greater amplitude oscillation in the system over time. The frequency causing the maximal amplitude is often called the resonant frequency. Resonance can be catastrophic, such as the Tacoma Narrows bridge that oscillated so strongly due to just 64 km/h winds that the bridge deck tore apart. Wikipedia: 1940 Tacoma Narrows Bridge Film of Collapse

Undamped Resonance

Damped Resonance