Derivative Help - Calculus

Full question: A 6-ft-tall person walks away from a 10-ft lamppost at a constant rate of 3ft/sec. What is the rate that the tip of the shadow moves away from the pole when the person is 10ft away from the pole? #Techniques #Calculus #Answered #Solutions

A rectangular storage container without a lid is to have a volume of 10 m^3 . The length of its base is twice the width. Material for the base costs $10 per square meter. Material for the sides costs $6 per square meter. Find the cost of materials for the least expensive such container. #Derivative #Solutions

Here is the technique to solve this question and how to find them in step-by-step Full question: A man launches his boat from point A on a bank of a straight river, 3 km wide, and wants to reach point B, 8 km downstream on the opposite bank, as quickly as possible. He could row his boat directly across the river to point C and then run to B, or he could row directly to B , or he could row to some point D between B and C and then run to B. If he can row 6 km/h and run 8 km/h, where should he land to reach B as soon as possible? (We assume that the speed of the water is negligible compared with the speed at which the man rows.) #Calculus #Derivative #Techniques #Solutions