In the above figure, point $$P$$ is at distance $$d_1 =4.00 \ m$$ from particle 1 $$(q_1 = -2e)$$ and distance $$d_2 =2.00 \ m$$ from particle 2 $$(q_2 =+2e)$$, with both particles fixed in place.
(a) With $$V=0$$ at infinity, what is $$V$$ at $$P$$?
If we bring a particle of charge $$q_3 =+2e$$ from infinity to $$P$$,
(b) how much work do we do and
(c) what is the potential energy of the three-particle system?