### 6.4: Linear Approximations

In this subunit, you will learn how to estimate future data points based on what you know about a previous data point and how it changed at that particular moment. This concept is extremely useful in the field of economics.

Read Section 6.4 (pages 139 and 140). In this reading, you will see how tangent lines can be used to locally approximate functions.

Watch this video until 39:00. Beyond 39:00, Jerison discusses quadratic approximations to functions, which are in a certain sense one step beyond linear approximations. If you are interested, please continue viewing the lecture to the end.

Work through problems 1-4 for Exercise 6.4. When you are done, check your answers against Appendix A.