
# 4: Applications of the Derivative


• 4.1: Newton's Method
Newton's Methos is a technique to approximate the solution to equations and is built around tangent lines. The main idea is that if x is sufficiently close to a root of f(x), then the tangent line to the graph at (x,f(x) will cross the x-axis at a point closer to the root than x.
• 4.2: Related Rates
The topic of "related rates" is the approach that knowing the rate at which one quantity is changing can determine the rate at which the other changes.
• 4.3: Optimization
In this section we apply the concepts of extreme values to solve "word problems," i.e., problems stated in terms of situations that require us to create the appropriate mathematical framework in which to solve the problem.
• 4.4: Differentials
The differential of x, denoted dx , is any nonzero real number (usually taken to be a small number). The differential of y, denoted dy, is dy=f′(x)dx.
• 4.E: Applications of Derivatives (Exercises)