Question

L *dI/dt+RI=E
L, R and E are constants. Write I as a function of t

Answer 1

\[\begin{align*}
L\frac{dI}{dt}+RI&=E\\\\
\frac{dI}{dt}+\frac{R}{L}I&=\frac{E}{L}
\end{align*}\]
You have a linear equation, so you can find an integrating factor:
\[\mu(t)=\exp\left(\int \frac{R}{L}~dt\right)=e^{R/L~t}\]
\[\begin{align*}e^{R/L~t}\frac{dI}{dt}+e^{R/L~t}\frac{R}{L}I&=e^{R/L~t}\frac{E}{L}\\\\

\frac{d}{dt}\left[e^{R/L~t}I\right]&=e^{R/L~t}\frac{E}{L}\end{align*}\]
and so on

Answer 2

i don't really understand what you did.

Answer 3

nevermind. I got it. Thanks

Answer 4

Yep no problem. Sorry for any confusion.