[latex]V_1= frac{kcdot 2Q}{ frac{asqrt2}{2} } = 2sqrt 2 frac{kQ}{a} \ V_2= frac{kcdot 3Q}{ frac{asqrt2}{2} } = 3sqrt 2 frac{kQ}{a} \ V_3= frac{kcdot 4Q}{ frac{asqrt2}{2} } = 4sqrt 2 frac{kQ}{a} \ V_4= frac{kcdot Q}{ frac{asqrt2}{2} } = sqrt 2 frac{kQ}{a} \ V=V_1+V_2+V_3+V_4 = 10sqrt 2 frac{kQ}{a} [/latex] [latex]vec E_1= frac{kcdot 2Q}{ (frac{asqrt2}{2})^2 } [frac{sqrt2}{2},-frac{sqrt2}{2}] = 4 frac{kQ}{a^2} [frac{sqrt2}{2},-frac{sqrt2}{2}] = [2sqrt 2, -2sqrt 2 ]frac{kQ}{a^2} \ vec E_2= frac{kcdot 3Q}{ (frac{asqrt2}{2})^2 } [frac{sqrt2}{2},frac{sqrt2}{2}] = 6 frac{kQ}{a^2} [frac{sqrt2}{2},frac{sqrt2}{2}] = [3sqrt 2, 3sqrt 2 ]frac{kQ}{a^2} \[/latex] [latex]vec E_3= frac{kcdot 4Q}{ (frac{asqrt2}{2})^2 } [-frac{sqrt2}{2},frac{sqrt2}{2}] = 8 frac{kQ}{a^2} [-frac{sqrt2}{2},frac{sqrt2}{2}] = [-4sqrt 2, 4sqrt 2 ]frac{kQ}{a^2} \ vec E_4= frac{kcdot Q}{ (frac{asqrt2}{2})^2 } [-frac{sqrt2}{2},-frac{sqrt2}{2}] = 2 frac{kQ}{a^2} [-frac{sqrt2}{2},-frac{sqrt2}{2}] = [-sqrt 2, -sqrt 2 ]frac{kQ}{a^2} \ vec E=vec E_1+vec E_2+vec E_3+vec E_4=[0 , 4sqrt 2 ] frac{kQ}{a^2}\ |vec E|=4sqrt 2 frac{kQ}{a^2}[/latex]
