Math Problem Statement

Jika diketahui g(x) = x - 1 dan (f o g)(x) = 2x^2 - 4x + 3, fungsi f(x) adalah .... A. x - 2 B. x + 2 C. x^2 + 2 D. 2x^2 - 1 E. 2x^2 + 1

Solution

To solve this problem, let's go through the composition of functions step-by-step. We're given:

  1. g(x)=x1g(x) = x - 1
  2. (fg)(x)=f(g(x))=2x24x+3(f \circ g)(x) = f(g(x)) = 2x^2 - 4x + 3

Our goal is to find f(x)f(x).

Step 1: Substitute g(x)g(x) into f(g(x))f(g(x))

Since g(x)=x1g(x) = x - 1, we replace g(x)g(x) in f(g(x))f(g(x)): f(x1)=2x24x+3f(x - 1) = 2x^2 - 4x + 3

Step 2: Determine the function f(x)f(x)

To find f(x)f(x), let u=x1u = x - 1. Then, x=u+1x = u + 1. Substitute x=u+1x = u + 1 into the expression 2x24x+32x^2 - 4x + 3:

  1. Substitute x=u+1x = u + 1 into x2x^2: x2=(u+1)2=u2+2u+1x^2 = (u + 1)^2 = u^2 + 2u + 1

  2. Substitute x=u+1x = u + 1 into 4x-4x: 4x=4(u+1)=4u4-4x = -4(u + 1) = -4u - 4

  3. Combine terms to find f(u)f(u): f(u)=2(u2+2u+1)4u4+3f(u) = 2(u^2 + 2u + 1) - 4u - 4 + 3 =2u2+4u+24u4+3= 2u^2 + 4u + 2 - 4u - 4 + 3 =2u2+1= 2u^2 + 1

So, f(x)=2x2+1f(x) = 2x^2 + 1.

Answer

The correct answer is: E. f(x)=2x2+1f(x) = 2x^2 + 1

Would you like further details or have any questions?


Related Questions

  1. How do we solve for f(x)f(x) if (fg)(x)(f \circ g)(x) has a different form?
  2. What are the steps to verify if two functions are inverses of each other?
  3. How would the solution change if g(x)g(x) was a more complex function?
  4. How do we compute the composition of three functions?
  5. What are real-world applications of function composition?

Tip

In function composition, always substitute the inner function result first, then simplify.

Ask a new question for Free

By Image

Drop file here or Click Here to upload

Math Problem Analysis

Mathematical Concepts

Function Composition
Quadratic Functions
Algebra

Formulas

Composition of functions: (f ∘ g)(x) = f(g(x))
Expansion of (a + b)^2 = a^2 + 2ab + b^2

Theorems

Function Composition

Suitable Grade Level

Grades 10-12