Math Problem Statement

Diketahui fungsi f: R → R dan g: R → R dirumuskan oleh f(x) = 5x - 2 dan g(x) = x^2. Rumus fungsi (f o g)(x) adalah ...

Solution

To solve this problem, we need to find the composition of two functions ff and gg, denoted as (fg)(x)(f \circ g)(x), which represents applying g(x)g(x) first and then applying ff to the result of g(x)g(x).

Given Functions

  • f(x)=5x2f(x) = 5x - 2
  • g(x)=x2g(x) = x^2

Composition (fg)(x)(f \circ g)(x)

To find (fg)(x)(f \circ g)(x), we substitute g(x)g(x) into f(x)f(x): (fg)(x)=f(g(x))(f \circ g)(x) = f(g(x)) Since g(x)=x2g(x) = x^2, this becomes: f(g(x))=f(x2)f(g(x)) = f(x^2) Now, substitute x2x^2 into the function f(x)f(x): f(x2)=5(x2)2f(x^2) = 5(x^2) - 2 Simplify this expression: f(x2)=5x22f(x^2) = 5x^2 - 2

Answer

The correct answer is:

  • Option D: 5x225x^2 - 2

Would you like a further breakdown of any step or a detailed explanation?


Here are some related questions to practice function composition and function properties:

  1. What is the result of (gf)(x)(g \circ f)(x) using the same functions f(x)=5x2f(x) = 5x - 2 and g(x)=x2g(x) = x^2?
  2. How would you find (ff)(x)(f \circ f)(x) for f(x)=5x2f(x) = 5x - 2?
  3. Can function composition be commutative, i.e., is (fg)(x)=(gf)(x)(f \circ g)(x) = (g \circ f)(x) always true?
  4. If f(x)=ax+bf(x) = ax + b and g(x)=cx+dg(x) = cx + d, how do you compute (fg)(x)(f \circ g)(x) in terms of aa, bb, cc, and dd?
  5. If f(x)f(x) and g(x)g(x) are both quadratic functions, is the composition (fg)(x)(f \circ g)(x) necessarily quadratic?

Tip: When composing functions, always apply the inner function first and then substitute the result into the outer function carefully to avoid errors.

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Math Problem Analysis

Mathematical Concepts

Function Composition
Algebra

Formulas

(f ∘ g)(x) = f(g(x))
f(x) = 5x - 2
g(x) = x^2

Theorems

Composition of Functions

Suitable Grade Level

Grades 10-12