1. 9.1 Inverse Variation

2. Inverse variation When one value increases, the other decreases.

3. Example Suppose that x and y vary inversely and x = 3 when y = -5. Write the function that models inverse variation.

4. Example Suppose that x and y vary inversely and x = 0.3 when y = 1.4. Write the function that models inverse variation.

5. Example Suppose that x and y vary inversely and x = 2 when y = 9. Write the function that models inverse variation. What is x when y = 12?

6. Example Suppose that x and y vary inversely and x = 12 when y = 7. Write the function that models inverse variation. What is y when x = 7?

7. Joint Variation Multiplication is direct variation Division is inverse variation Varies jointly implies all direct variation

8. Example

9. Write the function Z varies directly with y and inversely with r. Write the formula. Find k when z = 12, y = 5 and r = 4 Find z when y = 9 and r = 7.

10. Homework 11/7: #37 pg 491 1-6, 13-27