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2.6 Combinations of Functions: Composite Functions Arithmetic Combinations of Functions Composition of Functions Decomposition of Functions
A. If f(x) = 2x – 3 and g(x) = x 2  – 1 Find f(x) + g(x). Skeleton: (  ) + (  ) The nickname for f(x) + g(x) is _________.
If f(x) = 2x – 3 and g(x) = x 2  – 1 Find f(x) – g(x). Skeleton: (  ) – (  ) Nickname for f(x) – g(x) is ____________.
If f(x) = 2x – 3 and g(x) = x 2  – 1 Find f(x)g(x). Skeleton: (  )(  ) The nickname for f(x)g(x) is ___________
If f(x) = 2x – 3 and g(x) = x 2  – 1 Find  Skeleton: The nickname for this one is:
You try: f(x)=2x+1, g(x)=x 2 +2x-1 A) Find (f + g)(x) B) Find (f – g)(x) C) Find (f + g) (-1) D)Find (fg)(x).
B. Composition of Functions means f(g(x)), like “f of g of x” Plug g INTO f. Make skeleton of f first, and then plug in the whole g(x) expression
Write it as “f(g(x))” (means plug g into f) Write skeleton of f: (________) + 2 Into the blanks, put what g(x) is equal to. (  4 – x 2   ) + 2 Simplify: Find if f(x) = x + 2 and g(x) = 4 – x 2
Find if f(x) = x + 2 and g(x) = 4 – x 2 If asked to find
You try: f(x) = x 2 , g(x) = x - 1
Finding these from a graph: If I say “Find f(2),” the 2 is an X-VALUE! On a graph, you would go to the 2 on the x-axis, and look up and down until you find the graph called “f(x)” and you would find it’s Y-VALUE at the point. (Recall that “f(x)” is another way of saying “the  y-value  on this certain function.”)
Here is an example, “Find f(2)”
Find these from the graphs:
C. Decomposition of Functions It is an important skill in calculus to be able to take a fancy function and to break it down into simpler parts. Watch this: h(x) = (1 – x) 3  Imagine that fancy part on the inside were just a plain x. One function would be  and one would be  . If it said, “Write this as (fog)(x),” the g(x) would be the inside one, the embedded one.
Try: Find two functions f and  such that (fog)(x) = h(x).

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119 Powerpoint 2.6

  • 1. 2.6 Combinations of Functions: Composite Functions Arithmetic Combinations of Functions Composition of Functions Decomposition of Functions
  • 2. A. If f(x) = 2x – 3 and g(x) = x 2 – 1 Find f(x) + g(x). Skeleton: ( ) + ( ) The nickname for f(x) + g(x) is _________.
  • 3. If f(x) = 2x – 3 and g(x) = x 2 – 1 Find f(x) – g(x). Skeleton: ( ) – ( ) Nickname for f(x) – g(x) is ____________.
  • 4. If f(x) = 2x – 3 and g(x) = x 2 – 1 Find f(x)g(x). Skeleton: ( )( ) The nickname for f(x)g(x) is ___________
  • 5. If f(x) = 2x – 3 and g(x) = x 2 – 1 Find Skeleton: The nickname for this one is:
  • 6. You try: f(x)=2x+1, g(x)=x 2 +2x-1 A) Find (f + g)(x) B) Find (f – g)(x) C) Find (f + g) (-1) D)Find (fg)(x).
  • 7. B. Composition of Functions means f(g(x)), like “f of g of x” Plug g INTO f. Make skeleton of f first, and then plug in the whole g(x) expression
  • 8. Write it as “f(g(x))” (means plug g into f) Write skeleton of f: (________) + 2 Into the blanks, put what g(x) is equal to. ( 4 – x 2 ) + 2 Simplify: Find if f(x) = x + 2 and g(x) = 4 – x 2
  • 9. Find if f(x) = x + 2 and g(x) = 4 – x 2 If asked to find
  • 10. You try: f(x) = x 2 , g(x) = x - 1
  • 11. Finding these from a graph: If I say “Find f(2),” the 2 is an X-VALUE! On a graph, you would go to the 2 on the x-axis, and look up and down until you find the graph called “f(x)” and you would find it’s Y-VALUE at the point. (Recall that “f(x)” is another way of saying “the y-value on this certain function.”)
  • 12. Here is an example, “Find f(2)”
  • 13. Find these from the graphs:
  • 14. C. Decomposition of Functions It is an important skill in calculus to be able to take a fancy function and to break it down into simpler parts. Watch this: h(x) = (1 – x) 3 Imagine that fancy part on the inside were just a plain x. One function would be and one would be . If it said, “Write this as (fog)(x),” the g(x) would be the inside one, the embedded one.
  • 15. Try: Find two functions f and such that (fog)(x) = h(x).