Chapter 3.4, Problem 3.40P

Two long straight wires, carrying opposite uniform line charges $\pm \lambda$ , are situated on either side of a long conducting cylinder (Fig. 3.39). The cylinder(which carries no net charge) has radius R, and the wires are a distance a from theaxis. Find the potential.
   $\left[Answer:V\left(s,\varphi \right)=\frac{\lambda }{4\pi {\in }_0}\ln \left\{\frac{\left(s^2+a^2+2sa\cos \varphi \right)\left[{\left(sa/R\right)}^2+R^2-sa\cos \varphi \right]}{\left(s^2+a^2-2sa\cos \varphi \right)\left[{\left(sa/R\right)}^2+R^2+sa\cos \varphi \right]}\right\}\right]$