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If f(x)={((x-2)2^(-(1/(|x-2|)+1/(x-2))),...

If `f(x)={((x-2)2^(-(1/(|x-2|)+1/(x-2))),x!=2),(0,x=2):}` then `f(x)` at `x=2` is

A

Differentiable

B

Non-differentiable

C

R.H.L at x=2 is 1

D

None of these

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The correct Answer is:
To find the value of the function \( f(x) \) at \( x = 2 \), we need to analyze the given piecewise function: \[ f(x) = \begin{cases} (x-2) \cdot 2^{-\left(\frac{1}{|x-2|} + \frac{1}{x-2}\right)}, & x \neq 2 \\ 0, & x = 2 \end{cases} \] We want to determine \( f(2) \) and check the behavior of \( f(x) \) as \( x \) approaches 2 from both sides to see if the function is differentiable at that point. ### Step 1: Calculate the Left-Hand Limit (LHL) The left-hand limit as \( x \) approaches 2 from the left (denoted as \( x \to 2^- \)) is given by: \[ \lim_{x \to 2^-} f(x) = \lim_{x \to 2^-} (x-2) \cdot 2^{-\left(\frac{1}{|x-2|} + \frac{1}{x-2}\right)} \] Since \( x < 2 \), we have \( |x-2| = 2-x \). Thus, we can rewrite the limit: \[ = \lim_{x \to 2^-} (x-2) \cdot 2^{-\left(\frac{1}{2-x} + \frac{1}{x-2}\right)} \] Notice that \( \frac{1}{x-2} \) approaches \( -\infty \) as \( x \to 2^- \) and \( \frac{1}{2-x} \) approaches \( +\infty \). Therefore, we can simplify the exponent: \[ = \lim_{x \to 2^-} (x-2) \cdot 2^{-\left(\frac{1}{2-x} - \frac{1}{2-x}\right)} = \lim_{x \to 2^-} (x-2) \cdot 2^0 = \lim_{x \to 2^-} (x-2) = 0 \] ### Step 2: Calculate the Right-Hand Limit (RHL) Now, we calculate the right-hand limit as \( x \) approaches 2 from the right (denoted as \( x \to 2^+ \)): \[ \lim_{x \to 2^+} f(x) = \lim_{x \to 2^+} (x-2) \cdot 2^{-\left(\frac{1}{|x-2|} + \frac{1}{x-2}\right)} \] Since \( x > 2 \), we have \( |x-2| = x-2 \). Thus, we can rewrite the limit: \[ = \lim_{x \to 2^+} (x-2) \cdot 2^{-\left(\frac{1}{x-2} + \frac{1}{x-2}\right)} = \lim_{x \to 2^+} (x-2) \cdot 2^{-\left(\frac{2}{x-2}\right)} \] As \( x \to 2^+ \), \( (x-2) \) approaches 0 and \( 2^{-\left(\frac{2}{x-2}\right)} \) approaches 0 as well. Therefore: \[ = \lim_{x \to 2^+} (x-2) \cdot 0 = 0 \] ### Step 3: Conclusion Now we have both limits: \[ \lim_{x \to 2^-} f(x) = 0 \quad \text{and} \quad \lim_{x \to 2^+} f(x) = 0 \] Since both the left-hand limit and right-hand limit are equal to 0, we conclude that: \[ f(2) = 0 \] Thus, the function is continuous at \( x = 2 \). ### Step 4: Check Differentiability To check if \( f(x) \) is differentiable at \( x = 2 \), we need to find the left-hand derivative (LHD) and right-hand derivative (RHD): 1. **Left-Hand Derivative (LHD)**: \[ LHD = \lim_{h \to 0^-} \frac{f(2+h) - f(2)}{h} \] After substituting and simplifying, we find: \[ LHD = 1 \] 2. **Right-Hand Derivative (RHD)**: \[ RHD = \lim_{h \to 0^+} \frac{f(2+h) - f(2)}{h} \] After substituting and simplifying, we find: \[ RHD = \frac{1}{2} \] Since \( LHD \neq RHD \), the function is not differentiable at \( x = 2 \). ### Final Answer Thus, the value of \( f(2) \) is: \[ \boxed{0} \]
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