Differential Equations

First order DEs

IVPs, Direction Fields, Isoclines

Direction Fields, Autonomous DEs

Separable DEs, Exact DEs, Linear 1st order DEs

Numerical method: Euler (or Constant Slope)

Applications (Growth/Cooling/Circuits/Falling body)

Higher order DEs

IVPs/General solutions, Basic theory

Numerical methods for higher order DEs

Constant coefficient case: Undetermined Coefficients

Application: springs (free, damped, forced, pure resonance)

Application: Electrical Circuits

Laplace Transform (LT) methods

Inverse Laplace & Derivatives

1st Translation Thrm

Partial Fractions, completing the square

Unit Step Functions

SAGE can define piecewise functions like

x \ {\mapsto}\ \sin ( \frac{\pi \cdot x}{2} )
on (0, 1),
x \ {\mapsto}\ 1 - ( x - 1 )^2
on (1, 3),
x \ {\mapsto}\ -x
on (3, 5), as follows:

sage: f(x) = sin(x*pi/2)
sage: g(x) = 1-(x-1)^2
sage: h(x) = -x
sage: P = Piecewise([[(0,1), f], [(1,3),g], [(3,5), h]])
sage: latex(P)

However, at the moment only Laplace transforms of "piecewise polynomial" functions are implemented:

sage: f(x) = x^2+1      
sage: g(x) = 1-(x-1)^3
sage: P = Piecewise([[(0,1), f], [(1,3),g], [(3,5), h]])
sage: P.laplace(x,s)
(s^3 - 6)*e^(-s)/s^4 - ((2*s^2 + 2*s + 2)*e^(-s)/s^3) + (7*s^3 + 12*s^2 + 12*s + 6)*e^(-3*s)/s^4 + (-3*s - 1)*e^(-3*s)/s^2 + (5*s + 1)*e^(-5*s)/s^2 + (s^2 + 2)/s^3

2nd Translation Theorem

Derivative thrms, Solving DEs

Convolution theorem

Dirac Delta Function

Application: Lanchester's equations

Application: Electrical networks


Separation of Variables

Heat Equation., Fourier's solution

Fourier Series

Convergence, Dirichlet's theorem

Fourier Sine Series, Fourier Cosine Series

Heat Eqn. Ends at Zero

Heat Eqn. Both Ends Insulated