Categories: All - solution - method - polynomial - roots

by Taylor Brereton 9 years ago

803

ODE's

Differential equations can be classified and solved using various methods based on their characteristics. For second-order differential equations, solutions often involve determining the roots of the characteristic polynomial, which can be real, complex, or repeated.

ODE's

Is it separable?

Find the homogeneous solution

Find the particular solution

Solution: y(t) = c1e^(r1t) + c2e^(r2t)

Solution: y(t) = c1e^(λt)v + c2te^(λt)v + c2e^(λt)u

Can you integrate directly?

Use eigenvectors and eigenvalues

Variations of parameters method

Solution: integrate and solve for y

Solve using laplace transforms

Form the characteristic polynomial

Solution for non-homogeneous: y(t) = (homogenous solution) + (particular solution)

Repeated Roots

Solution: y(t) = c1e^(r1t) + c2te^(r2t)

Solve using eigenvectors and eigenvalues if the O.D.E. can be written as a system of first order differential equations; otherwise, use laplace transforms.

Solution: y(t) = c1e^(αt)[cos(βt)p - sin(βt)q] + c2e^(αt)[sin(βt)p - cos(βt)q]

Is it homogeneous?

Solution: separate, integrate, and solve for y

Is the O.D.E. second order?

Complex (Imaginary) Roots

Solution: y(t) = e^(αt)[c1cos(βt) + c2sin(βt)]

Subtopic

Undetermined coefficients method

Use the integrating factor method

Solution: calculate the integrating factor, multiply by the integrating factor, integrate, and solve for y.

Real Roots

Solution: y(t) = c1e^(λ1t)v1 + c2e^(λ2t)v2

Can the O.D.E. be written as a system of first order differential equations?

Solving O.D.E.'s

Is the O.D.E first order?