How do you use double integrals to find the surface area of two intersecting cylinders of radius 1?
To find the area of one cylinder you integrate over dh and dt (theta) like this: r.dt.dh with dt from 0 to 2pi radians. The intersection changes the limits of theta. Assuming that the center of the second cylinder is exactly R from the other cylinder then theta goes from 0 to 2pi*2/3. The 2/3 is because you have removed 120 degrees.
