"The third point charge should be placed at a location at which the forces on the third charge due to each of the other two point charges cancel. There can be no such place except on the line between the two point charges."(adsbygoogle = window.adsbygoogle || []).push({});

i need to be able to prove a similar statement mathematically (meaning i need to prove that the third point charge cannot be on the right or left of the system but that it must be in the middle). i have no idea how to go about this, please show me how to prove the above statement mathematically so that i can work out my hw assignment problem on my own. (the link below is to the problem containing the statement above---scroll to the top of the second page.)

i tried solving this using coulombs law, but it requires that i make an initial assumption for my R---which i cant do without first proving on which area within the system i need to place q_3

http://www.physics.wisc.edu/undergrads/courses/spring09/248/HWSolutions/HW5Solutions.pdf

**Physics Forums | Science Articles, Homework Help, Discussion**

Dismiss Notice

Join Physics Forums Today!

The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

# Homework Help: How to prove an electrostatics concept mathematically

**Physics Forums | Science Articles, Homework Help, Discussion**