physics

Compute the electric field vector at all 4 locations in the following figure. The metallic sheet has a uniform charge of 300nC distributed on the surface. you can find the figure in the attachment 

the computation can quickly become tedious due to the many small pieces; thus I recommend, you create a spreadsheet (Google Spreadsheet, Excel, or OpenCalc) with several columns, the first column contains the x vector, the second column the y vector of the element, then in the next column you compute the electric field from a point charge from that point, next you sum all those point charges to find the net electric field.

I need a sketch and explanation