Math Problem Statement

(fog)(x) = f[g(x)] = f[3/x] = (3/x - 1)/(2x) = 2x/(3 - x)

Solution

The problem presented is a composition of functions, specifically (fg)(x)=f(g(x))(f \circ g)(x) = f(g(x)). Let’s analyze it step by step:

  1. Given Functions:

    • g(x)=3xg(x) = \frac{3}{x},
    • f(u)=u2f(u) = \frac{u}{2}, where u=g(x)u = g(x).
  2. Composition of Functions:

    • Substituting g(x)g(x) into f(u)f(u), we get: f(g(x))=f(3x)=3x2.f(g(x)) = f\left(\frac{3}{x}\right) = \frac{\frac{3}{x}}{2}.
  3. Simplification:

    • Simplify f(3x)f\left(\frac{3}{x}\right): f(g(x))=3x2=32x.f(g(x)) = \frac{\frac{3}{x}}{2} = \frac{3}{2x}.
  4. Further Operations:

    • The second step in the image shows subtracting 1 from the numerator: 3x12.\frac{\frac{3}{x} - 1}{2}.

    • Combine terms: 3xx2.\frac{\frac{3 - x}{x}}{2}.

    • Final simplification gives: 2x3x.\frac{2x}{3 - x}.

Thus, (fg)(x)=2x3x(f \circ g)(x) = \frac{2x}{3 - x}, which matches the result in the image.

Would you like me to elaborate on any specific step or concept?


Related Questions

  1. What are the domain restrictions for (fg)(x)(f \circ g)(x) in this case?
  2. How does the composition of functions change if f(u)=u2f(u) = u^2?
  3. Can you explain the concept of domain and range in function composition?
  4. How would you differentiate (fg)(x)(f \circ g)(x) if f(x)f(x) and g(x)g(x) were both differentiable?
  5. What is the significance of (fg)(x)(f \circ g)(x) in real-world applications?

Tip: Always check for domain restrictions when dealing with compositions to ensure the result is valid.

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Math Problem Analysis

Mathematical Concepts

Function Composition
Simplification of Rational Expressions

Formulas

Composition of functions: (f ∘ g)(x) = f(g(x))
Simplifying fractions: (a/b)/(c/d) = (a * d)/(b * c)

Theorems

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Suitable Grade Level

Grades 10-12