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Let f (x) =(2 |x| -1)/(x-3) Range of ...

Let `f (x) =(2 |x| -1)/(x-3)`
Range of the values of 'k' for which `f (x) = k` has exactly two distinct solutions:

A

`(-2 ,(1)/(3))`

B

`(-2,1]`

C

`(0,(2)/(3)]`

D

`(-oo, -2)`

Text Solution

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To find the range of values of \( k \) for which the equation \( f(x) = k \) has exactly two distinct solutions, we start with the function defined as: \[ f(x) = \frac{2|x| - 1}{x - 3} \] ### Step 1: Analyze the function for different cases of \( x \) Since \( f(x) \) involves the absolute value function, we need to consider two cases based on the sign of \( x \). **Case 1:** \( x \geq 0 \) For \( x \geq 0 \), we have \( |x| = x \). Thus, the function simplifies to: \[ f(x) = \frac{2x - 1}{x - 3} \] **Case 2:** \( x < 0 \) For \( x < 0 \), we have \( |x| = -x \). Thus, the function simplifies to: \[ f(x) = \frac{-2x - 1}{x - 3} \] ### Step 2: Set up the equations for both cases We need to find the values of \( k \) such that \( f(x) = k \) has exactly two distinct solutions. **For Case 1:** Setting \( f(x) = k \): \[ \frac{2x - 1}{x - 3} = k \] Cross-multiplying gives: \[ 2x - 1 = k(x - 3) \implies 2x - 1 = kx - 3k \] Rearranging this leads to: \[ (2 - k)x = -3k + 1 \implies x = \frac{-3k + 1}{2 - k} \] **For Case 2:** Setting \( f(x) = k \): \[ \frac{-2x - 1}{x - 3} = k \] Cross-multiplying gives: \[ -2x - 1 = k(x - 3) \implies -2x - 1 = kx - 3k \] Rearranging this leads to: \[ (-2 - k)x = -3k + 1 \implies x = \frac{-3k + 1}{-2 - k} \] ### Step 3: Determine the conditions for distinct solutions For \( f(x) = k \) to have exactly two distinct solutions, one solution must come from each case. This means we need to ensure that the two expressions for \( x \) yield valid solutions. 1. **From Case 1:** \( x = \frac{-3k + 1}{2 - k} \) must be non-negative. 2. **From Case 2:** \( x = \frac{-3k + 1}{-2 - k} \) must be negative. ### Step 4: Solve the inequalities **For Case 1:** \( \frac{-3k + 1}{2 - k} \geq 0 \) This occurs when: - The numerator and denominator are both positive, or both negative. 1. **Numerator:** \( -3k + 1 \geq 0 \implies k \leq \frac{1}{3} \) 2. **Denominator:** \( 2 - k > 0 \implies k < 2 \) **For Case 2:** \( \frac{-3k + 1}{-2 - k} < 0 \) This occurs when: - The numerator is positive and the denominator is negative. 1. **Numerator:** \( -3k + 1 > 0 \implies k < \frac{1}{3} \) 2. **Denominator:** \( -2 - k < 0 \implies k > -2 \) ### Step 5: Combine the results From the inequalities, we have: 1. From Case 1: \( k \leq \frac{1}{3} \) and \( k < 2 \) 2. From Case 2: \( k < \frac{1}{3} \) and \( k > -2 \) Combining these gives: \[ -2 < k < \frac{1}{3} \] ### Conclusion The range of values of \( k \) for which \( f(x) = k \) has exactly two distinct solutions is: \[ \boxed{(-2, \frac{1}{3})} \]
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