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Statement I f(x) = |x| sin x is differen...

Statement I f(x) = |x| sin x is differentiable at x = 0.
Statement II If g(x) is not differentiable at x = a and h(x) is differentiable at x = a, then g(x).h(x) cannot be differentiable at x = a

A

A. Statement I is correct, Statement II is also correct, Statement II is the correct explanation of Statement I

B

B. Statement I is correct, Statement II is also correct, Statement II is not the correct explanation of Statement I

C

C. Statement I is correct, Statement II is incorrect

D

D. Statement I is incorrect, Statement II is correct.

Text Solution

AI Generated Solution

The correct Answer is:
To solve the given problem, we need to analyze both statements one by one. ### Step 1: Analyze Statement I The first statement is about the function \( f(x) = |x| \sin x \) and whether it is differentiable at \( x = 0 \). 1. **Definition of the Function**: - For \( x \geq 0 \): \( f(x) = x \sin x \) - For \( x < 0 \): \( f(x) = -x \sin x \) 2. **Finding the Derivative**: We need to find the left-hand derivative and the right-hand derivative at \( x = 0 \). - **Right-hand derivative** (\( f'(0^+) \)): \[ f'(0^+) = \lim_{h \to 0^+} \frac{f(h) - f(0)}{h} = \lim_{h \to 0^+} \frac{h \sin h - 0}{h} = \lim_{h \to 0^+} \sin h = \sin(0) = 0 \] - **Left-hand derivative** (\( f'(0^-) \)): \[ f'(0^-) = \lim_{h \to 0^-} \frac{f(h) - f(0)}{h} = \lim_{h \to 0^-} \frac{-h \sin h - 0}{h} = \lim_{h \to 0^-} -\sin h = -\sin(0) = 0 \] 3. **Conclusion for Statement I**: Since both the left-hand derivative and the right-hand derivative at \( x = 0 \) are equal (both are 0), we conclude that \( f(x) \) is differentiable at \( x = 0 \). Thus, Statement I is **True**. ### Step 2: Analyze Statement II The second statement claims that if \( g(x) \) is not differentiable at \( x = a \) and \( h(x) \) is differentiable at \( x = a \), then \( g(x) h(x) \) cannot be differentiable at \( x = a \). 1. **Understanding the Statement**: - Let \( g(x) \) be a function that is not differentiable at \( x = a \). - Let \( h(x) \) be a function that is differentiable at \( x = a \). 2. **Product of Functions**: The product \( g(x) h(x) \) can potentially be differentiable even if one of the functions is not differentiable. A classic example is: - Let \( g(x) = |x| \) (not differentiable at \( x = 0 \)). - Let \( h(x) = x \) (differentiable everywhere). Then: \[ g(x) h(x) = |x| \cdot x = x^2 \] which is differentiable at \( x = 0 \). 3. **Conclusion for Statement II**: Since we found a counterexample where \( g(x) h(x) \) is differentiable even though \( g(x) \) is not, we conclude that Statement II is **False**. ### Final Conclusion - Statement I is **True**. - Statement II is **False**.
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