Find the area of the surface generated when the curve with equation y=cosh(x) is rotated through 2 pi radians about the x axis, with 2<=x<=6

Use the formula for the surface area of revolution, which requires dy/dx. So find dy/dx = sinh(x) and substitute dy/dx and y into the formula with the limits provided in the question (2 and 6). Then evaluate the integral and the answer should be 2pi * (1/4sinh(12) - 1/4sinh(4) + 2).