Equation Icon  ( ) ∫ d3y rirj δij rirj 4π δij --------A6A-= − 4π --2-− -A-A4- + -------+ 𝒪 (εRA ), (128 ) N∕B |⃗x − ⃗y | rA 4rA 4r A 3εR1r1 ∫ 3 i j ( ij i j i j i j i j i j ) --d-y--r1r2 = − 4π − -δ---− --r1r12--+ r12r12-+ r12r12 − -r1r12-+ -r12r2--- N ∕B |⃗x − ⃗y|r31r32 r12S r1r12S2 r212S2 r312S r1r2S2 r12r2S2 +𝒪 (εRA ). (129 )