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Solve the following differential equation by using integrating factors. You may assume that...

a. y' + P(x)y = Q(x)
b. y'' - P(x)y' + Q(x)y = R(x)
c. dy/dx + Py = Q
d. ∫(Pdx) = Q

1 Answer

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Final answer:

The student's question is regarding the solution of differential equations using integrating factors. An integrating factor, calculated as e²∫(∫(Pdx)), is multiplied by the differential equation, transforming it into a form where the left side is the derivative of the product of the integrating factor and y, leading to a simple integration to solve for y.

Step-by-step explanation:

The student is asking how to solve various differential equations using integrating factors. Integrating factors are a technique applied to first-order linear differential equations, which involves multiplication by an appropriately chosen function, the integrating factor. The method transforms a non-exact differential equation into an exact one, simplifying the process of integration.

For an equation of the form dy/dx + Py = Q, the integrating factor, often denoted as μ(x), is found by computing e²∫(Pdx). Multiplying the entire differential equation by this integrating factor allows us to rewrite the left side as the derivative of a product of the integrating factor and the unknown function y, which can then be easily integrated with respect to x. After integrating, the solution for y can be found, often involving the integration of Q multiplied by the integrating factor.

User Eric Willigers
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