1. CMC South Kathleen Strange UNDERSTANDING FUNCTIONS (c) 2013 Kathleen Strange

2. This is a function.This is not a function. UNDERSTANDING FUNCTIONS (c) 2013 Kathleen Strange

3. This is a function.This is not a function. UNDERSTANDING FUNCTIONS (c) 2013 Kathleen Strange

4. This is a function.This is not a function. UNDERSTANDING FUNCTIONS (c) 2013 Kathleen Strange

5. This is a function.This is not a function. UNDERSTANDING FUNCTIONS (c) 2013 Kathleen Strange

6. This is a function.This is not a function. UNDERSTANDING FUNCTIONS (c) 2013 Kathleen Strange

7. Why are these functions? Why are these NOT functions? MAKE A CONJECTURE (c) 2013 Kathleen Strange

8. This is a functionThis is not a function THINK ABOUT DOMAIN AND RANGE (c) 2013 Kathleen Strange

9.  Does each element of the domain correspond to exactly one element of the range?  If yes, then the graph represents a function. UNDERSTANDING FUNCTIONS (c) 2013 Kathleen Strange

10. IS THIS A FUNCTION? WHY OR WHY NOT?

11.  Since the equation x^2 = 9 has two solutions, x = +3 and x = – 3, students might think that sqrt(9) is +–3. However, if we want sqrt(x) to be a function of x, we need to choose one of these square roots. The square root function, g(x) = sqrt(x), is defined to be the positive square root of x for any positive x. (c) 2013 Kathleen Strange WHY ARE FUNCTIONS IMPORTANT? http://ime.math.arizona.edu/progressions/