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e^(|sinx|)+e^(-|sinx|)+4a=0 will have ex...

`e^(|sinx|)+e^(-|sinx|)+4a=0` will have exactly four different solutions in `[0,2pi]` if. `a in R` (b) `a in [-3/4,-1/4]` `a in [(-1-e^2)/(4e),oo]` (d) none of these

A

`a in R`

B

`a in [- e/4, -1/4]`

C

`a in [(-1-e^(2))/(4e), oo]`

D

none of these

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To solve the equation \( e^{|\sin x|} + e^{-|sin x|} + 4a = 0 \) and determine the conditions on \( a \) for which it has exactly four different solutions in the interval \([0, 2\pi]\), we can follow these steps: ### Step 1: Rewrite the Equation We start with the equation: \[ e^{|\sin x|} + e^{-|sin x|} + 4a = 0 \] This can be rewritten as: \[ e^{|\sin x|} + \frac{1}{e^{|\sin x|}} + 4a = 0 \] ### Step 2: Substitute \( t \) Let \( t = e^{|\sin x|} \). Since \( |\sin x| \) varies between 0 and 1, \( t \) will vary between \( e^0 = 1 \) and \( e^1 = e \). ### Step 3: Transform the Equation Substituting \( t \) into the equation gives: \[ t + \frac{1}{t} + 4a = 0 \] This simplifies to: \[ t + \frac{1}{t} = -4a \] ### Step 4: Analyze the Function Define the function: \[ f(t) = t + \frac{1}{t} \] We need to analyze this function for \( t \) in the interval \([1, e]\). ### Step 5: Find the Range of \( f(t) \) To find the minimum and maximum values of \( f(t) \): - The derivative \( f'(t) = 1 - \frac{1}{t^2} \). - Setting \( f'(t) = 0 \) gives \( t^2 = 1 \) or \( t = 1 \) (since \( t \) is positive). - Evaluate \( f(t) \) at the endpoints: - \( f(1) = 1 + 1 = 2 \) - \( f(e) = e + \frac{1}{e} \) Calculating \( f(e) \): \[ f(e) = e + \frac{1}{e} \approx 2.718 + 0.368 = 3.086 \] Thus, the range of \( f(t) \) for \( t \in [1, e] \) is: \[ [2, e + \frac{1}{e}] \] ### Step 6: Set Up the Inequality For the equation \( -4a \) to fall within the range of \( f(t) \): \[ -4a \in [2, e + \frac{1}{e}] \] This leads to: \[ 2 \leq -4a \leq e + \frac{1}{e} \] ### Step 7: Solve for \( a \) From \( -4a \geq 2 \): \[ a \leq -\frac{1}{2} \] From \( -4a \leq e + \frac{1}{e} \): \[ a \geq -\frac{e + \frac{1}{e}}{4} \] ### Step 8: Final Range for \( a \) Thus, we have: \[ -\frac{e + \frac{1}{e}}{4} \leq a \leq -\frac{1}{2} \] ### Step 9: Check the Options Now we check the provided options: - (a) \( a \in \mathbb{R} \) - Incorrect. - (b) \( a \in \left[-\frac{3}{4}, -\frac{1}{4}\right] \) - Incorrect. - (c) \( a \in \left[-\frac{1 + e^2}{4e}, \infty\right) \) - Incorrect. - (d) None of these - Correct. ### Conclusion The correct answer is: **(d) none of these.**

To solve the equation \( e^{|\sin x|} + e^{-|sin x|} + 4a = 0 \) and determine the conditions on \( a \) for which it has exactly four different solutions in the interval \([0, 2\pi]\), we can follow these steps: ### Step 1: Rewrite the Equation We start with the equation: \[ e^{|\sin x|} + e^{-|sin x|} + 4a = 0 \] This can be rewritten as: ...
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