Calculate the potential due to a thin charged rod of length L at the points along and perpendicular to the length. Charge per unit length on the rod is `lambda`.

Explanation

`dV=(kdq)/((b^(2)+x^(2))^(1//2))=(klambdadx)/((b^(2)+x^(2))^(1//2))`
`V=underset(a)overset(a+L)int(klambdadx)/((b^(2)+x^(2))^(1//2))=klambdaunderset(a)overset(a+L)int(dx)/((b^(2)+x^(2))^(1//2))`
`V=klambdal n|((a+L)+sqrt(b^(2)+(L+a)^(2)))/(a+sqrt(b^(2)+a^(2)))|`