Lesson 3-3 Writing Functions Obj: The student will be able to 1) Identify independent and dependent variables 2) Write an equation in function notation and evaluate a function for given input values HWK: Day 1 p 183 13-19 all Day 2 p 183 20-26 all, 28 Vocab: 1) independent variable 2) dependent variable 3) function rule 4) function notation

Determine a relationship between the x and y values. Write an equation. Time worked (hrs) Amount earned ($) 1 5 2 10 3 15 4 20

Ex 2) X Y 1 -2 2 -1 3 4

Identify the independent and dependent variables in each situation. Ex 3) In the winter, more electricity is used when the temperature goes down, and less is used when the temperature rises. Ex 4) The cost of shipping a package is based on its weight

Ex 5) The faster Ron walks, the quicker he gets home Ex 6) A company charges $10 per hour to rent a jackhammer

Function notation: f(x) reads “f of x or function of x” The dependent variable is a function of the independent variable. y is a function of x y = f(x)

Identify the independent and dependent variables Identify the independent and dependent variables. Write an equation in function notation for each situation. Ex 7) A lawyer’s fee is $200 per hour for her services Ex 8) The admission fee to a local carnival is $8. Each ride cost $1.50

Evaluate each function for the given input values Ex 9) For f(x) = 5x find f(x) when x = 6 and x = 7.5 Ex 10) For g(t) = 2.30t + 10 find g(t) when t = 2 and t = -5

Ex 11) For h(x) = 1 2 x – 3 find h(x) when x = 12 and x = -8

Ex 12) What would be a reasonable domain and range for each situation? The cost of shipping a package depends on its weight Purchase price of CD’s

Ex 13) Manuel has already sold $20 worth of tickets to the school play Ex 13) Manuel has already sold $20 worth of tickets to the school play. He has 4 tickets left to sell at $2.50 per ticket. Write a function to describe how much money Manuel can collect from selling tickets. Find the reasonable domain and range for the function.