The Area of the Surface Generated by Revolving a Graph About Any Line
  We discuss a general formula for the area of the surface that is generated by a graph $[t_0, t_1] \to \mathbb R^2$ sending $t \mapsto \bigl(x(t), y(t) \bigr)$ revolved around a general line $L: A x + B y = C$. As a corollary, we obtain a formula for the area of the surface formed by revolving $y = f(x)$ around the line $y = m x + k$. 
Edray Herber Goins and Talitha M. Washington
math.HO math.MG