First order differential equations using separation of variables

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Differential Equations of the form dydx=f(x)g(y)\frac{dy}{dx} = f(x)g(y)

We have learned how to solve differential equations which depend on either xx or yy, but not both at the same time. It turns out that we can combine the techniques we have seen already to solve what are called separable differential equations. As the name suggests, a separable differential equation is one that can be separated into parts dealing with only one variable in each part. For example, we could use this technique to solve the differential equation

dydx=xy\frac{dy}{dx} = \frac{x}{y}

In this case, we now have a derivative that depends on the solution and the value of xx at the same time.

We will again solve this using the Change of Variables Theorem, so the solution will look a lot like what we did for the example dydx=y\frac{dy}{dx} = y.

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