Math Problem Statement

find functions f and g so that f o g = H

H(x)=|4x+6|

Solution

To find functions f(x)f(x) and g(x)g(x) such that (fg)(x)=H(x)(f \circ g)(x) = H(x), where H(x)=4x+6H(x) = |4x + 6|, we can follow these steps:

  1. Start with H(x)H(x): H(x)=4x+6H(x) = |4x + 6| We aim to express H(x)H(x) as (fg)(x)=f(g(x))(f \circ g)(x) = f(g(x)), which means H(x)H(x) should be represented as a composition of two functions ff and gg.

  2. Define g(x)g(x): Let g(x)g(x) represent the inner function. A natural choice for g(x)g(x) is the expression inside the absolute value: g(x)=4x+6g(x) = 4x + 6 So, now we have g(x)=4x+6g(x) = 4x + 6.

  3. Define f(x)f(x): The outer function f(x)f(x) should apply the absolute value to the result of g(x)g(x). Thus, we define f(x)f(x) as: f(x)=xf(x) = |x| This ensures that when we apply ff to g(x)g(x), we get H(x)H(x).

  4. Check the composition: Now, let's check if (fg)(x)=f(g(x))(f \circ g)(x) = f(g(x)) gives us H(x)H(x): f(g(x))=f(4x+6)=4x+6f(g(x)) = f(4x + 6) = |4x + 6| which matches H(x)H(x).

Thus, the functions are:

  • g(x)=4x+6g(x) = 4x + 6
  • f(x)=xf(x) = |x|

Would you like further details or have any questions?

Here are 5 related questions for further exploration:

  1. How would the composition change if H(x)H(x) did not include an absolute value?
  2. Can you generalize this approach to other types of transformations (e.g., square roots)?
  3. What happens to the composition if we replace 4x+64x + 6 with a different linear function?
  4. How does this approach work if f(x)f(x) and g(x)g(x) are non-linear functions?
  5. How would the composition change if we considered H(x)=(4x+6)H(x) = -(4x + 6) instead?

Tip: When solving composition problems, it's useful to identify the "inner" and "outer" operations by analyzing the structure of the function.

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Math Problem Analysis

Mathematical Concepts

Function Composition
Absolute Value
Linear Functions

Formulas

(f o g)(x) = f(g(x))
H(x) = |4x + 6|

Theorems

Composition of Functions

Suitable Grade Level

Grades 10-12