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The domain and range (Range = f (x): x `in` domain off ) of the function `f (x)=(x^2 -3x +2)/(x^2 +x -6)`are

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To find the domain and range of the function \( f(x) = \frac{x^2 - 3x + 2}{x^2 + x - 6} \), we will follow these steps: ### Step 1: Determine the Domain The domain of a function is the set of all possible input values (x-values) for which the function is defined. For a rational function, we need to ensure that the denominator is not equal to zero. 1. **Set the denominator equal to zero**: \[ x^2 + x - 6 = 0 \] 2. **Factor the quadratic**: \[ (x + 3)(x - 2) = 0 \] 3. **Find the values of x that make the denominator zero**: \[ x + 3 = 0 \quad \Rightarrow \quad x = -3 \] \[ x - 2 = 0 \quad \Rightarrow \quad x = 2 \] 4. **State the domain**: The function is undefined at \( x = -3 \) and \( x = 2 \). Therefore, the domain of \( f(x) \) is: \[ \text{Domain} = \{ x \in \mathbb{R} \mid x \neq -3, x \neq 2 \} \] ### Step 2: Determine the Range To find the range, we need to analyze the values that \( f(x) \) can take. 1. **Rewrite the function**: We can simplify \( f(x) \): \[ f(x) = \frac{(x - 1)(x - 2)}{(x + 3)(x - 2)} \] Here, we notice that \( x - 2 \) cancels out, but we must remember that \( x = 2 \) is not in the domain. 2. **Simplified function**: The function simplifies to: \[ f(x) = \frac{x - 1}{x + 3} \quad \text{for } x \neq 2 \] 3. **Find horizontal asymptotes**: As \( x \) approaches infinity, the function approaches: \[ \lim_{x \to \infty} f(x) = 1 \] This suggests that \( y = 1 \) is a horizontal asymptote. 4. **Determine values at critical points**: We check the values of \( f(x) \) at the points where the function is undefined: - \( f(-3) \) is undefined. - \( f(2) \) is undefined. 5. **Check for values that cannot be reached**: To find if there are specific values that \( f(x) \) cannot take, we set: \[ \frac{x - 1}{x + 3} = y \] Rearranging gives: \[ y(x + 3) = x - 1 \quad \Rightarrow \quad x(y - 1) = -3y - 1 \] \[ x = \frac{-3y - 1}{y - 1} \] This expression is undefined when \( y = 1 \), indicating that \( f(x) \) cannot equal 1. 6. **Final range**: Since \( f(x) \) approaches 1 but never reaches it, and we also have \( f(2) \) undefined, we conclude: \[ \text{Range} = \{ y \in \mathbb{R} \mid y \neq 1 \} \] ### Final Answer: - **Domain**: \( \{ x \in \mathbb{R} \mid x \neq -3, x \neq 2 \} \) - **Range**: \( \{ y \in \mathbb{R} \mid y \neq 1 \} \)
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ML KHANNA-FUNCTIONS-PROBLEM SET (3)
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