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Consider the function f(x)={{:(x^(2)",",...

Consider the function `f(x)={{:(x^(2)",",xgt2),(3x-2",",xle2):}`. Which one of the following statements is correct in respect of the above function?

A

f(x) is derivable but not continuous at x=2.

B

f(x) if continuous but not derivalble at x=2.

C

f(x) is neither continuous nor derivable at x=2.

D

f(x) is continuous as well as derivable at x=2.

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To determine the correct statement about the function \( f(x) \) defined as: \[ f(x) = \begin{cases} x^2 & \text{if } x > 2 \\ 3x - 2 & \text{if } x \leq 2 \end{cases} \] we need to check the continuity and differentiability of the function at \( x = 2 \). ### Step 1: Check Continuity at \( x = 2 \) To check if the function is continuous at \( x = 2 \), we need to find the left-hand limit, right-hand limit, and the value of the function at that point. 1. **Left-hand limit** as \( x \) approaches \( 2 \): \[ \lim_{x \to 2^-} f(x) = \lim_{h \to 0} f(2 - h) = \lim_{h \to 0} (3(2 - h) - 2) = \lim_{h \to 0} (6 - 3h - 2) = 4 \] 2. **Right-hand limit** as \( x \) approaches \( 2 \): \[ \lim_{x \to 2^+} f(x) = \lim_{h \to 0} f(2 + h) = \lim_{h \to 0} (2 + h)^2 = \lim_{h \to 0} (4 + 4h + h^2) = 4 \] 3. **Value of the function at \( x = 2 \)**: \[ f(2) = 3(2) - 2 = 4 \] Since the left-hand limit, right-hand limit, and the value of the function at \( x = 2 \) are all equal to \( 4 \), we conclude that: \[ \text{The function is continuous at } x = 2. \] ### Step 2: Check Differentiability at \( x = 2 \) Next, we need to check if the function is differentiable at \( x = 2 \) by finding the left-hand derivative and right-hand derivative. 1. **Left-hand derivative**: \[ f'(x) = 3 \quad \text{for } x < 2 \] \[ \lim_{h \to 0} \frac{f(2 - h) - f(2)}{-h} = \lim_{h \to 0} \frac{(3(2 - h) - 2) - 4}{-h} = \lim_{h \to 0} \frac{(6 - 3h - 2) - 4}{-h} = \lim_{h \to 0} \frac{-3h}{-h} = 3 \] 2. **Right-hand derivative**: \[ f'(x) = 2x \quad \text{for } x > 2 \] \[ \lim_{h \to 0} \frac{f(2 + h) - f(2)}{h} = \lim_{h \to 0} \frac{(2 + h)^2 - 4}{h} = \lim_{h \to 0} \frac{(4 + 4h + h^2) - 4}{h} = \lim_{h \to 0} \frac{4h + h^2}{h} = \lim_{h \to 0} (4 + h) = 4 \] Since the left-hand derivative (3) does not equal the right-hand derivative (4), we conclude that: \[ \text{The function is not differentiable at } x = 2. \] ### Conclusion Based on the analysis, we find that: - The function is continuous at \( x = 2 \). - The function is not differentiable at \( x = 2 \). Thus, the correct statement is: **The function is continuous but not derivable at \( x = 2 \).**

To determine the correct statement about the function \( f(x) \) defined as: \[ f(x) = \begin{cases} x^2 & \text{if } x > 2 \\ 3x - 2 & \text{if } x \leq 2 \end{cases} ...
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NDA PREVIOUS YEARS-FUNCTIONS, LIMIT, CONTINUITY AND DIFFERENTIABILITY-MCQs
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