Problem

COST-EFFICIENT DESIGN A cable is to be run from a power plant on one side of a river 900 m...

COST-EFFICIENT DESIGN A cable is to be run from a power plant on one side of a river 900 meters wide to a factory on the other side, 3,000 meters downstream. The cable will be run in a straight line from the power plant to some point P on the opposite bank and then along the bank to the factory. The cost of running the cable across the water is $5 per meter, while the cost over land is $4 per meter. Let x be the distance from P to the point directly across the river from the power plant. Express the cost of installing the cable as a function of x.