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Statement-1 : Let f : [1, oo) rarr [1, o...

Statement-1 : Let `f : [1, oo) rarr [1, oo)` be a function such that `f(x) = x^(x)` then the function is an invertible function.
Statement-2 : The bijective functions are always invertible .

A

Statement-1 is True, Statement-2 is True, Statement-2 is a correct explanation for Statement-1.

B

Statement-1 is True, Statement-2 is True, Statement-2 is NOT a correct explanation for Statement-1.

C

Statement -1 is False, Statement -2 is False

D

Statement -1 is False, Statement -2 is True

Text Solution

AI Generated Solution

The correct Answer is:
To determine whether the function \( f(x) = x^x \) defined on the interval \([1, \infty)\) is invertible, we need to check if it is a bijective function, meaning it is both one-to-one (injective) and onto (surjective). ### Step 1: Check if the function is one-to-one (injective) To check if \( f(x) \) is one-to-one, we can analyze its derivative. 1. Start with the function: \[ y = f(x) = x^x \] 2. Take the natural logarithm of both sides: \[ \log y = x \log x \] 3. Differentiate both sides with respect to \( x \): \[ \frac{dy}{dx} = \frac{d}{dx}(x^x) = x^x \left( \log x + 1 \right) \] 4. Now, analyze the derivative \( \frac{dy}{dx} \): - For \( x \geq 1 \), \( \log x \geq 0 \), hence \( \log x + 1 > 0 \). - Therefore, \( \frac{dy}{dx} > 0 \) for all \( x \geq 1 \). Since the derivative is positive, \( f(x) \) is an increasing function, which implies that it is one-to-one. ### Step 2: Check if the function is onto (surjective) To check if \( f(x) \) is onto, we need to determine the range of the function: 1. Calculate \( f(1) \): \[ f(1) = 1^1 = 1 \] 2. Calculate the limit as \( x \) approaches infinity: \[ \lim_{x \to \infty} f(x) = \lim_{x \to \infty} x^x = \infty \] 3. Since \( f(x) \) is continuous and increasing from \( 1 \) to \( \infty \), the range of \( f(x) \) is \( [1, \infty) \). 4. The co-domain of \( f(x) \) is also \( [1, \infty) \). Since the range equals the co-domain, \( f(x) \) is onto. ### Conclusion Since \( f(x) = x^x \) is both one-to-one and onto, we conclude that \( f(x) \) is invertible. ### Statement Validation - **Statement 1**: The function \( f(x) = x^x \) is an invertible function. **True**. - **Statement 2**: Bijective functions are always invertible. **True**. Both statements are correct.
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