A charge of 0.883 nC is placed at the origin. Another charge of 0.347 nC is placed at x1 = 13.1 cm on the x-axis.(adsbygoogle = window.adsbygoogle || []).push({});

At which point on the x-axis does this potential have a minimum?

I do know a few things:

A necessary condition for the potential to have a minimum is that its derivative is 0.

The minimum is between the two charges.

I need to take the derivative of:

k*q1/r - k*q2/(r-x1), but I'm not sure about how to go about that?

I'm not looking for the answer. Just need some help setting this up.

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# Homework Help: Minimum Potential

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