General: Fuel Efficiency At what speed should a tugboat travel upstream so as to use the...

General: Fuel Efficiency At what speed should a tugboat travel upstream so as to use the least amount of fuel to reach its destination? If the tugboat’s speed through the water is v and the speed of the current (relative to the land) is c, then the energy used is proportional to . Find the velocity v that minimizes the energy E(v). Your answer will depend upon c, the speed of the current.