#### transgalactic

##### Banned

http://i27.tinypic.com/4jxj7o.jpg

i tried to solve it like this example

http://i26.tinypic.com/xghb4g.jpg

i tried to imagine it in this way:

http://i28.tinypic.com/24pwdvl.jpg

[latex]C_1=\frac{2\epsilon_0}{d-a}\\[/latex]

[latex]C_2=\frac{k\epsilon_0}{d}\\[/latex]

[latex]C_3=\frac{2\epsilon_0}{d-a}\\[/latex]

[latex]\frac{1}{C}=\frac{1}{C_1}+\frac{1}{C_2}+\frac{1}{C_3}[/latex]

is it ok?