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Let f(x)=(-1)^([x^(3)]), where [.] denot...

Let `f(x)=(-1)^([x^(3)])`, where [.] denotest the greatest integer function. Then,

A

f(x) is discontinuous at x`=n^(1//3), n in Z`

B

f(3/2)=1

C

`f'(0)=0"for all "x in (-1,1)`

D

none of these

Text Solution

AI Generated Solution

The correct Answer is:
To solve the problem, we need to analyze the function \( f(x) = (-1)^{[\sqrt[3]{x}]} \), where \([.]\) denotes the greatest integer function (also known as the floor function). We will determine the points of discontinuity and evaluate the function at specific values. ### Step 1: Identify points of discontinuity The greatest integer function \([\cdot]\) is discontinuous at integer values. Therefore, we need to find when \(\sqrt[3]{x}\) is an integer. 1. Set \(\sqrt[3]{x} = n\), where \(n\) is an integer. 2. This implies \(x = n^3\). Thus, the function \(f(x)\) is discontinuous at \(x = n^3\) for all integers \(n\). ### Step 2: Write the points of discontinuity The points of discontinuity for \(f(x)\) are at \(x = n^3\) where \(n \in \mathbb{Z}\). ### Step 3: Evaluate \(f\left(\frac{3}{2}\right)\) Now, we need to evaluate \(f\left(\frac{3}{2}\right)\): 1. Calculate \(\left(\frac{3}{2}\right)^3 = \frac{27}{8} = 3.375\). 2. Now apply the greatest integer function: \([\sqrt[3]{3.375}] = [3.375] = 3\). 3. Therefore, \(f\left(\frac{3}{2}\right) = (-1)^3 = -1\). ### Step 4: Analyze the derivative \(f'(x)\) Since \(f(x)\) is discontinuous at \(x = n^3\), we cannot find \(f'(x)\) at these points. Thus, \(f'(x)\) does not exist at \(x = n^3\). ### Conclusion From the analysis, we conclude: - The function \(f(x)\) is discontinuous at \(x = n^3\) for all integers \(n\). - \(f\left(\frac{3}{2}\right) = -1\). - The derivative \(f'(x)\) does not exist at \(x = n^3\). ### Final Answer The correct option is that \(f(x)\) is discontinuous at \(x = n^3\) for \(n \in \mathbb{Z}\). ---

To solve the problem, we need to analyze the function \( f(x) = (-1)^{[\sqrt[3]{x}]} \), where \([.]\) denotes the greatest integer function (also known as the floor function). We will determine the points of discontinuity and evaluate the function at specific values. ### Step 1: Identify points of discontinuity The greatest integer function \([\cdot]\) is discontinuous at integer values. Therefore, we need to find when \(\sqrt[3]{x}\) is an integer. 1. Set \(\sqrt[3]{x} = n\), where \(n\) is an integer. 2. This implies \(x = n^3\). ...
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