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Let a function f (x)= be such that f(x)=...

Let a function `f (x)=` be such that `f(x)=||x^(2)-3|-2|`.
Equation has 2 solutions if :

A

`lambda gt 2`

B

`lambda lt 2`

C

`1 lt lambda lt 2`

D

`lambda ge 2`

Text Solution

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The correct Answer is:
To solve the problem, we need to analyze the function \( f(x) = ||x^2 - 3| - 2| \) and determine the conditions under which the equation \( f(x) = \lambda \) has exactly 2 solutions. ### Step 1: Understand the Function The function \( f(x) \) consists of nested absolute values. We can break it down step by step. 1. Start with the inner function \( g(x) = x^2 - 3 \). 2. The absolute value \( |g(x)| = |x^2 - 3| \) will have a minimum value of 0 when \( x^2 = 3 \), i.e., at \( x = \pm \sqrt{3} \). ### Step 2: Graph the Inner Function The graph of \( g(x) = x^2 - 3 \) is a parabola opening upwards with its vertex at (0, -3). The points where it intersects the x-axis are \( x = -\sqrt{3} \) and \( x = \sqrt{3} \). ### Step 3: Graph the Absolute Value The graph of \( |g(x)| = |x^2 - 3| \) reflects the part of the parabola that is below the x-axis above the x-axis. Thus, the graph will touch the x-axis at \( x = -\sqrt{3} \) and \( x = \sqrt{3} \) and rise upwards from there. ### Step 4: Shift Down by 2 Next, we consider \( |g(x)| - 2 \): - The graph of \( |g(x)| \) is shifted down by 2 units. The new minimum value will be at \( y = -2 \) when \( x = -\sqrt{3} \) and \( x = \sqrt{3} \). ### Step 5: Final Absolute Value Now we consider the function \( f(x) = ||g(x)| - 2| \). This means we take the absolute value of the entire expression, which will reflect any part of the graph that is below the x-axis back above it. ### Step 6: Analyze the Graph for Solutions To find when \( f(x) = \lambda \) has exactly 2 solutions, we need to analyze the horizontal line \( y = \lambda \): - If \( \lambda < -2 \): The line does not intersect the graph at all (0 solutions). - If \( \lambda = -2 \): The line touches the graph at two points (1 solution). - If \( -2 < \lambda < 0 \): The line intersects the graph at four points (4 solutions). - If \( \lambda = 0 \): The line intersects at four points (4 solutions). - If \( 0 < \lambda < 1 \): The line intersects at six points (6 solutions). - If \( \lambda = 1 \): The line intersects at six points (6 solutions). - If \( 1 < \lambda < 2 \): The line intersects at four points (4 solutions). - If \( \lambda = 2 \): The line intersects at four points (4 solutions). - If \( \lambda > 2 \): The line intersects the graph at exactly two points (2 solutions). ### Conclusion Thus, the equation \( f(x) = \lambda \) has exactly 2 solutions if: \[ \lambda > 2 \]
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