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If f(x)={{:(-e^(-x)+k,",",xle0),(e^(x)+1...

If `f(x)={{:(-e^(-x)+k,",",xle0),(e^(x)+1,",",0ltxlt1),(ex^(2)+lambda,",",xge1):}` is one-one and monotonically increasing `AA x in R`, then

A

maximum value of k is 1

B

maximum value of k is 3

C

minimum value of `lambda` is 0

D

minimum value of `lambda` is 1

Text Solution

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The correct Answer is:
To solve the problem, we need to analyze the function \( f(x) \) defined in three parts and ensure that it is one-one and monotonically increasing for all \( x \in \mathbb{R} \). ### Step 1: Analyze the function in each interval The function \( f(x) \) is defined as: 1. \( f(x) = -e^{-x} + k \) for \( x \leq 0 \) 2. \( f(x) = e^x + 1 \) for \( 0 < x < 1 \) 3. \( f(x) = e x^2 + \lambda \) for \( x \geq 1 \) ### Step 2: Check monotonicity in each interval **For \( x \leq 0 \):** - The derivative \( f'(x) = e^{-x} \) (since the derivative of \( -e^{-x} \) is \( e^{-x} \)). - Since \( e^{-x} > 0 \) for all \( x \), \( f(x) \) is increasing in this interval. **For \( 0 < x < 1 \):** - The derivative \( f'(x) = e^x \). - Since \( e^x > 0 \) for all \( x \), \( f(x) \) is increasing in this interval. **For \( x \geq 1 \):** - The derivative \( f'(x) = 2ex \). - Since \( 2ex > 0 \) for all \( x \geq 1 \), \( f(x) \) is increasing in this interval. ### Step 3: Ensure continuity at the boundaries To ensure that \( f(x) \) is one-one, we need to check the values at the boundaries \( x = 0 \) and \( x = 1 \). **At \( x = 0 \):** - \( f(0) = -e^0 + k = -1 + k \) **At \( x = 1 \):** - \( f(1) = e^1 + 1 = e + 1 \) For \( f(x) \) to be continuous at \( x = 0 \): \[ -1 + k < e + 1 \] This implies: \[ k < e + 2 \] **At \( x = 1 \):** - \( f(1) = e + 1 \) and \( f(1) = e(1)^2 + \lambda = e + \lambda \) For continuity at \( x = 1 \): \[ e + 1 = e + \lambda \] This implies: \[ \lambda = 1 \] ### Step 4: Ensure that \( f(x) \) is one-one Since \( f(x) \) is increasing in all intervals and continuous, it is one-one. ### Conclusion The conditions for \( f(x) \) to be one-one and monotonically increasing for all \( x \in \mathbb{R} \) are: - \( k < e + 2 \) - \( \lambda = 1 \) ### Final Result Thus, the values of \( k \) and \( \lambda \) are: - \( \lambda \leq 1 \) - \( k < e + 2 \)

To solve the problem, we need to analyze the function \( f(x) \) defined in three parts and ensure that it is one-one and monotonically increasing for all \( x \in \mathbb{R} \). ### Step 1: Analyze the function in each interval The function \( f(x) \) is defined as: 1. \( f(x) = -e^{-x} + k \) for \( x \leq 0 \) 2. \( f(x) = e^x + 1 \) for \( 0 < x < 1 \) 3. \( f(x) = e x^2 + \lambda \) for \( x \geq 1 \) ...
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