Determine the volume of the solid bound between the sphere x^2+y^2+z^2=R^2 and the cylinder x^2 +y^2=r^2, where R>r (such shapes are called spherical rings or napkin rings).
The intensity I of light varies inversely as the square of the distance D from the source. If the intensity of illumination on a screen 5 ft from a light is 4 foot candles, find the intensity on a screen 20 ft from the light.
Sketch the region bounded by f(x) = 1+2ex, g(x) = 1+4eāx, x = ā1 and x = 1. Using calculus, find the area of the region, showing all the working. Express your answer in simplified exact form.