# Thread: Need help differentiating

1. ## Need help differentiating

i= v/r (1-e^-Rt/L)

How would i go about differentiating this formula to get di/dt? Would I use the product rule or another rule?

2. ## Re: Need help differentiating

use chain rule for differentiating
i=v/r(1-e^(-rt/l))
di/dt=(r/l)*e^(-rt/l)

3. ## Re: Need help differentiating

That is not quite correct. prasum forgot the initial v/r.

4. ## Re: Need help differentiating

correct the answer is di/dt=(v/l)*e^(-rt/l)