Math Problem Statement

1-x+x2, where R is the set of all real numbers. If (g o f)(x) =9x2-9x+3, determine a and b, where (g o f) is the composite function.

Solution

To solve for aa and bb in the composite function (gf)(x)=9x29x+3(g \circ f)(x) = 9x^2 - 9x + 3, we first need to understand the definitions and relationships of the functions involved in the composition.

Given:

  • f(x)=1x+x2f(x) = 1 - x + x^2
  • (gf)(x)=9x29x+3(g \circ f)(x) = 9x^2 - 9x + 3

We need to determine g(x)g(x). Let's assume:

  • f(x)=1x+x2f(x) = 1 - x + x^2
  • Let y=f(x)y = f(x)
  • Then y=1x+x2y = 1 - x + x^2

We can write g(y)g(y) as a function of yy, where g(f(x))=g(y)g(f(x)) = g(y).

Given (gf)(x)=9x29x+3(g \circ f)(x) = 9x^2 - 9x + 3, we know that g(1x+x2)=9x29x+3g(1 - x + x^2) = 9x^2 - 9x + 3.

Let's assume g(y)=ay+bg(y) = ay + b. This is a linear function in terms of yy.

We know that: g(1x+x2)=9x29x+3g(1 - x + x^2) = 9x^2 - 9x + 3

By substituting y=1x+x2y = 1 - x + x^2 into g(y)g(y): g(1x+x2)=a(1x+x2)+bg(1 - x + x^2) = a(1 - x + x^2) + b =a(1x+x2)+b= a(1 - x + x^2) + b =a(1)+a(x)+a(x2)+b= a(1) + a(-x) + a(x^2) + b =aax+ax2+b= a - ax + ax^2 + b

We need this to be equal to 9x29x+39x^2 - 9x + 3.

So, we compare coefficients: ax2=9x2ax^2 = 9x^2 ax=9x-ax = -9x a+b=3a + b = 3

From ax2=9x2ax^2 = 9x^2: a=9a = 9

From ax=9x-ax = -9x: 9x=9x-9x = -9x

From a+b=3a + b = 3: 9+b=39 + b = 3 b=39b = 3 - 9 b=6b = -6

Thus, the values of aa and bb are: a=9a = 9 b=6b = -6

So, the function g(y)g(y) is: g(y)=9y6g(y) = 9y - 6

Do you have any questions or need further details?

Here are 5 more questions you might be interested in:

  1. How do you find the derivative of a composite function?
  2. What are the properties of polynomial functions?
  3. Can you explain the concept of function composition with more examples?
  4. How do you determine the inverse of a function?
  5. What are some applications of composite functions in real life?

Tip: When working with composite functions, always ensure to clearly define the inner and outer functions and how they transform inputs step-by-step.

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Math Problem Analysis

Mathematical Concepts

Function Composition
Quadratic Equations
Linear Functions

Formulas

Composite Function Definition
Quadratic Equation Solution

Theorems

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Suitable Grade Level

Grades 10-12