A first [url=#]order[/url] linear differential equation can be written in the form[br][math]\frac{dy}{dx}+P\left(x\right)y=Q\left(x\right)[/math][br]A method to solve this kind of differential equation is to use integrating factor [math]e^{\int Pdx}[/math].[br]The purpose of this applet is to facilitate [url=#]practice[/url] solving these differential equations.[br]Follow instructions given on the applet. Some of the answers involve absolute values and sgn function because of the piecewise nature of integrand involved. One may use [math]\left|t\right|=t[/math] and [math]sgn\left(t\right)=1[/math] to compare the user answer without sgn function.