= Cylinder surface charge induced by an exterior line
{title2=$\sigma=-\frac{\lambda(b^2-a^2)}{2\pi a(b^2+a^2-2ab\cos\theta)}$}
For the real line at radius $b>a$ and polar angle measured toward it, the exterior radial field gives $\sigma(\theta)=-\lambda(b^2-a^2)/[2\pi a(b^2+a^2-2ab\cos\theta)]$. Its integral around the circumference is $-\lambda$ per unit axial length. At $b=2a$, this becomes $-3\lambda/[2\pi a(5-4\cos\theta)]$. The nearer surface has larger induced charge magnitude.
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