One of the main aspects of Geometric applications of differentiation which also has real world application is Problems involving maxima and minima. You could be asked to find what value of x maximises the profit function or what value of x minimises costs. It is one of the more interesting, but harder topics in this topic as it draws real life implications from the previous exercise on maximising and minimising.
See this video for a tutorial on how to solve these types of problems or see the examples below.
See this video for a tutorial on how to solve these types of problems or see the examples below.