1. Econ 201/202 Review of Essential Math and Graphing Skills

2. What do you need to know? Calculating and interpreting slopes of graphs –Linear and non-linear functions Calculating and interpreting areas under a graph –Geometric areas: triangles, rectangles –More sophisticated – integrals (or summing up) Systems of equations –Interpreting the results –Simultaneous equations and equilibrium

3. Slope of linear function FIGURE 1A-3 Plotting Price and Quantity Points in a Graph Demand Curve: Graphs of Two Variables (price and quantity)

4. Appendix FIGURE 1A-4 Calculating the Slope of a Line Graphs of Two Variables Slopes of Lines

5. Appendix FIGURE 1A-5 Showing Three Variables on a Graph Graphs of Two Variables Taking into Account More Than Two Variables on a Graph

6. Appendix FIGURE 1A-6 Graphing the Positive Relationship between Income and Consumption Graphs of Two Variables Positive and Negative Relationships

7. Appendix Graphs of Two Variables Are Graphs of Economic Relationships Always Straight Lines? The graphs of relationships between two economic variables that we have drawn so far have been straight lines. The relationship between two variables is linear when it can be represented by a straight line. Few economic relationships are actually linear.

8. Appendix Graphs of Two Variables Slopes of Nonlinear Curves FIGURE 1A-8 The Slope of a Nonlinear Curve

9. Appendix Formulas Formulas for the Areas of a Rectangle and a Triangle FIGURE 1A-9 Showing a Firm’s Total Revenue on a Graph

10. Appendix Formulas Formulas for the Areas of a Rectangle and a Triangle FIGURE 1A-10 The Area of a Triangle

11. Appendix Formulas Formula for a Percentage Change One important formula is the percentage change. The percentage change is the change in some economic variable, usually from one period to the next, expressed as a percentage.

12. Appendix Formulas Summary of Using Formulas 1Make sure you understand the economic concept that the formula represents. 2Make sure you are using the correct formula for the problem you are solving. 3Make sure that the number you calculate using the formula is economically reasonable. For example, if you are using a formula to calculate a firm’s revenue and your answer is a negative number, you know you made a mistake somewhere. Whenever you must use a formula, you should follow these steps: