Function Composition Equation

Solve \(f \circ g(x) = g \circ f(x)\)

🎥 Video Explanation


📝 Question

Given: \[ f(x)=x^2,\quad g(x)=2^x \]

Find solution of:

\[ f(g(x)) = g(f(x)) \]

  • A. \(\mathbb{R}\)
  • B. \(\{0\}\)
  • C. \(\{0,2\}\)
  • D. none of these

✅ Solution

🔹 Step 1: Compute Both Sides

\[ f(g(x)) = f(2^x) = (2^x)^2 = 2^{2x} \]

\[ g(f(x)) = g(x^2) = 2^{x^2} \]

🔹 Step 2: Equate

\[ 2^{2x} = 2^{x^2} \]

Since base is same:

\[ 2x = x^2 \]

🔹 Step 3: Solve

\[ x^2 – 2x = 0 \]

\[ x(x-2)=0 \]

\[ x=0 \text{ or } x=2 \]

🔹 Final Answer

\[ \boxed{\{0,2\}} \]

✔️ Option C

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