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Explore the combination of functions to analyze population and supply dynamics. Graphing functions, interpret significance, and calculate compositions.
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Combining Functions Lesson 5.1
Functions to Combine • Enter these functions into your calculator
Combining Functions • Consider the following expressions • Predict what will be the result if you graph
Combining Functions • Turn off the two original functions (F4) • Use them in theexpression for thecombined function • How does this differ from a parabola?
Application • Given two functions having to do with population • P(x) is the number of people • S(x) is the number of people who can be supplied with resources such as food, utilities, etc. • Graph these two functions • Window at 0 < x < 100 and 0 < y < 1000
Population and Supply • Viewing the two functions • Population • Supply • What is the significance of S(x) – P(x) • What does it look like – graph it
Population and Supply • What does it mean? • When should we be concerned?
Population and Supply • Per capita food supply could be a quotient • When would we be concerned on this formula?Set window-5 < y < 5
Combinations Using Tables • Determine the requested combinations
Assignment A • Lesson 5.1A • Page 346 • Exercises 1 – 25 odd, 61, 62
Composition of Functions • Value fed to first function • Resulting value fed to second function • End result taken from second function
Composition of Functions • Notation for composition of functions: • Alternate notation:
Try It Out • Given two functions: • p(x) = 2x + 1 • q(x) = x2 - 3 • Then p ( q(x) ) = • p (x2 - 3) = • 2 (x2 - 3) + 1 = • 2x2 - 5 • Try determining q ( p(x) )
Try It Out • q ( p(x) ) = • q ( 2x + 1) = • (2x + 1)2 – 3 = • 4x2 + 4x + 1 – 3 = • 4x2 + 4x - 2
Using the Calculator • Given • Define these functions on your calculator
WHY ?? Using the Calculator Now try the following compositions: • g( f(7) ) • f( g(3) ) • g( f(2) ) • f( g(t) ) • g( f(s) )
Using the Calculator • Is it also possible to have a composition of the same function? • g( g(3.5) ) = ???
Composition Using Graphs Do the composition of k( j(x) )
Composition Using Graphs • It is easier to see what the function is doing if we look at the values ofk(x), j(x), and then k( j(x) ) in tables:
Composition Using Graphs • Results of k( j(x) )
Composition With Tables • Consider the following tables of values:
Assignment B • Lesson 5.1B • Page 347 • Exercises 27 – 77 EOO