5-4 writing a function rule. ex. 1 writing from a table o ask “how do i get from x to f(x)?” o...
TRANSCRIPT
5-4 Writing a Function Rule
Ex. 1 Writing from a Table
O Ask “How do I get from x to f(x)?”
O Add 4 to x each time
O f(x) = x + 4
O How do I get from x to y
O x times itselfO y = x2
x f(x)1 52 63 74 8
x y1 13 96 369 81
Your PracticeO Write Function
Rule
O multiply x by 2O y = 2x
O Write Function Rule
O Add 2 to xO y = x + 2
x y1 22 43 64 8
x y1 32 43 54 6
Ex. 2/3 Story ProblemsO The exhibit at the left is a scale model of a desk
top computer. It is about 20 times the size of a normal sized desk top computer.
O A. Write a function ruleO B. Find length of space bar if 5 inches on regular
computer.O A. Larger is 20 times normal
O L = 20nO B. Use function rule
O L = 20nO L = 20(5)O L = 100 inches
Story Problems Cont.O Suppose you buy a word-processing
software package for $199. You charge $15 per hour for word processing. Write a rule to describe your profit as a function of the number of hours you work.
O Describe how to find the profitO Profit is 15 dollars per hour – cost of
software package.O P = 15d – 199
Your PracticeO A carpenter buys finishing nails by the pound.
Each pound of nails costs $1.19. Write a function rule to describe this relationship. How much do 12 lbs of finishing nails cost?
O Function RuleO Total cost is price per pound times number of
poundsO c = 1.19p
O Cost of 12 lbsO c = 1.19pO c = 1.19(12)O c = $14.28