To solve the initial value problem dydx=2y\frac{dy}{dx} = 2ydxdy=2y with y(0)=3y(0) = 3y(0)=3, what is the first step?
Separate variables: 1ydy=2dx\frac{1}{y} dy = 2 dxy1dy=2dx.
Multiply by the integrating factor e2xe^{2x}e2x.
Set y=0y=0y=0.
Differentiate the equation.