Math Problem Statement

Diketahui f(x) = x + 3 dan (g ∘ f)(x) = x^2 + 2x - 5. Tentukan fungsi g(x)!

Solution

The image you provided contains a mathematical problem in Indonesian. It can be translated as:


7. Diketahui f(x)=x+3f(x) = x + 3 dan (gf)(x)=x2+2x5(g \circ f)(x) = x^2 + 2x - 5. Tentukan fungsi g(x)g(x)!


This problem asks to find the function g(x)g(x), given that f(x)=x+3f(x) = x + 3 and the composition (gf)(x)=x2+2x5(g \circ f)(x) = x^2 + 2x - 5.

Solution Outline:

We are given:

  1. f(x)=x+3f(x) = x + 3
  2. (gf)(x)=g(f(x))=x2+2x5(g \circ f)(x) = g(f(x)) = x^2 + 2x - 5

Now, (gf)(x)(g \circ f)(x) means that we first apply the function f(x)f(x) and then apply g(x)g(x) to the result of f(x)f(x). So, to find g(x)g(x), we need to express gg as a function of f(x)f(x).

Steps:

  • f(x)=x+3f(x) = x + 3
  • So, g(f(x))=g(x+3)=x2+2x5g(f(x)) = g(x + 3) = x^2 + 2x - 5

Let’s solve this equation for g(u)g(u) where u=f(x)=x+3u = f(x) = x + 3.

This gives:

g(u)=(u3)2+2(u3)5g(u) = (u - 3)^2 + 2(u - 3) - 5

Simplifying this expression will give the function g(u)g(u).

Let me know if you'd like a step-by-step breakdown of the simplification process!

Would you like the details or have any questions? Here are some related questions that could help further your understanding:

  1. What is function composition, and how is it applied in this problem?
  2. How do you find the inverse of a function, and when is it necessary?
  3. How would this problem change if f(x)f(x) were a different function?
  4. How do transformations of functions like shifting and scaling work?
  5. What are some common applications of function composition in real-world scenarios?

Tip: When dealing with function compositions, it’s helpful to rewrite the composition explicitly step by step to avoid confusion.

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Math Problem Analysis

Mathematical Concepts

Function Composition
Quadratic Functions

Formulas

g(f(x)) = g(x + 3) = x^2 + 2x - 5

Theorems

Composition of Functions

Suitable Grade Level

Grades 10-12