Math Problem Statement

consider the initial value problem. dy/dt+2y=6, y(0)=0. find a particular solution to the non homogenoues differential equation

Solution

The given initial value problem is:

dydt+2y=6,y(0)=0\frac{dy}{dt} + 2y = 6, \quad y(0) = 0

This is a first-order linear non-homogeneous differential equation. To solve it, we will use the method of integrating factors.

Step 1: Identify the components

The equation is of the form:

dydt+P(t)y=Q(t)\frac{dy}{dt} + P(t)y = Q(t)

where P(t)=2P(t) = 2 and Q(t)=6Q(t) = 6.

Step 2: Compute the integrating factor

The integrating factor μ(t)\mu(t) is given by:

μ(t)=eP(t)dt=e2dt=e2t\mu(t) = e^{\int P(t) \, dt} = e^{\int 2 \, dt} = e^{2t}

Step 3: Multiply the entire equation by the integrating factor

Multiply both sides of the differential equation by e2te^{2t}:

e2tdydt+2e2ty=6e2te^{2t} \frac{dy}{dt} + 2 e^{2t} y = 6 e^{2t}

The left side of this equation is the derivative of e2tye^{2t} y, so we rewrite the equation as:

ddt(e2ty)=6e2t\frac{d}{dt} \left( e^{2t} y \right) = 6 e^{2t}

Step 4: Integrate both sides

Now, integrate both sides with respect to tt:

ddt(e2ty)dt=6e2tdt\int \frac{d}{dt} \left( e^{2t} y \right) \, dt = \int 6 e^{2t} \, dt

This gives:

e2ty=3e2t+Ce^{2t} y = 3 e^{2t} + C

where CC is the constant of integration.

Step 5: Solve for y(t)y(t)

Now, solve for y(t)y(t):

y(t)=3+Ce2ty(t) = 3 + C e^{-2t}

Step 6: Apply the initial condition

We are given the initial condition y(0)=0y(0) = 0. Substituting t=0t = 0 and y(0)=0y(0) = 0 into the equation:

0=3+Ce00 = 3 + C e^{0}

0=3+C0 = 3 + C

C=3C = -3

Step 7: Write the particular solution

Thus, the particular solution to the differential equation is:

y(t)=33e2ty(t) = 3 - 3 e^{-2t}

Final Answer:

The particular solution to the initial value problem is:

y(t)=33e2ty(t) = 3 - 3 e^{-2t}


Would you like more details on any part of the solution? Here are some related questions to expand the topic:

  1. How can we solve a non-homogeneous differential equation using the method of undetermined coefficients?
  2. What happens if the initial condition were different (e.g., y(0)=1y(0) = 1)?
  3. How do you identify whether a differential equation is homogeneous or non-homogeneous?
  4. How does the choice of the integrating factor affect the solution process?
  5. Can the method of integrating factors be applied to second-order differential equations?

Tip: For a first-order linear differential equation, the method of integrating factors is usually the simplest approach, but always make sure to carefully compute the integrating factor!

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Math Problem Analysis

Mathematical Concepts

Differential Equations
Initial Value Problems
Integrating Factor Method

Formulas

Integrating Factor: μ(t) = e^∫P(t)dt
Solution Formula: y(t) = (1/μ(t)) * ∫[Q(t)μ(t)]dt + C/μ(t)

Theorems

Linear First-Order Differential Equation Theorem

Suitable Grade Level

Grades 11-12 and College Level