What is the difference between refraction and reflection? Refraction only happens in gases.
In refraction, light travels from one medium to another.
Reflection only happens in gases.
In reflection, light travels from one medium to another.

See diagram.we use washers to get the area and we will be integrating with respect to xouter radius is the  distance between y = e^x and y = -1    inner radius of washer is the distance between y = 1 and y = -1    the area of one cross-section of a washer is    solid lies between x = 0 and x = 2. the volume is    if you need this expanded, then    the question doesn't say to evaluate, so we're done.