Hi. I'm reading a differential equation book to prime myself best for my signals and systems class I'm in, and I've ran into some confusion. If I had a differential equation like so: [tex]y'(t) + \int y(t)dt = f(t)[/tex] (1) What would you say the order is? The definition says "the order of a differential equation is the highest derivative that appears in the equation." Would I say it's a second order differential equation because: [tex] h(t) = \int y(t)dt[/tex] (2) meaning: [tex] h''(t) = y'(t)[/tex] (3) and substituting (2) and (3) into (1): [tex]h''(t) + h(t) = f(t)[/tex] (4) If asked to solve such a differential equation, would I first solve (4) and then differentiate h(t) to find y(t), the original function of t in question?