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If lim(x to a) f(x)=lim(x to a) [f(x)]...

If `lim_(x to a) f(x)=lim_(x to a) [f(x)] and f(x) ` is non-constant continuous function, where [.] denotes the greatest integer function, then

A

`underset(x to a)lim` f(x) is an integer

B

`underset(x to a)lim` f(x) is not an integer

C

f(x) has a local maximum at x=a

D

f(x) has a local minimum at x=a

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The correct Answer is:
To solve the problem, we need to analyze the given limits involving the function \( f(x) \) and the greatest integer function \( [f(x)] \). ### Step-by-Step Solution: 1. **Understanding the Given Limits:** We are given that: \[ \lim_{x \to a} f(x) = \lim_{x \to a} [f(x)] \] where \( f(x) \) is a non-constant continuous function and \( [.] \) denotes the greatest integer function. 2. **Rearranging the Equation:** We can rearrange the equation as follows: \[ \lim_{x \to a} f(x) - \lim_{x \to a} [f(x)] = 0 \] This implies: \[ \lim_{x \to a} (f(x) - [f(x)]) = 0 \] 3. **Taking the Limit:** Since both limits exist, we can take the limit inside: \[ f(a) - [f(a)] = 0 \] This means: \[ f(a) = [f(a)] \] Hence, \( f(a) \) must be an integer. 4. **Analyzing the Continuity of \( f(x) \):** Since \( f(x) \) is a non-constant continuous function, it cannot be constant over any interval. Thus, it must either be increasing or decreasing. 5. **Considering Local Maxima and Minima:** - If \( f(x) \) has a local maximum at \( x = a \), then: \[ \lim_{x \to a^-} f(x) \geq f(a) \quad \text{and} \quad \lim_{x \to a^+} f(x) \leq f(a) \] However, this would imply that \( [f(x)] \) would not equal \( f(x) \) at points close to \( a \), leading to a contradiction since \( f(x) \) is continuous. - If \( f(x) \) has a local minimum at \( x = a \), then: \[ \lim_{x \to a^-} f(x) \leq f(a) \quad \text{and} \quad \lim_{x \to a^+} f(x) \geq f(a) \] In this case, \( f(x) \) can equal \( [f(x)] \) for values approaching \( a \), maintaining continuity. 6. **Conclusion:** Therefore, \( f(a) \) must be an integer, and \( f(x) \) can only have a local minimum at \( x = a \). Thus, the conclusion is that \( f(a) \) is an integer and \( f(x) \) has a local minimum at \( x = a \). ### Final Answer: - \( f(a) \) is an integer. - \( f(x) \) has a local minimum at \( x = a \).

To solve the problem, we need to analyze the given limits involving the function \( f(x) \) and the greatest integer function \( [f(x)] \). ### Step-by-Step Solution: 1. **Understanding the Given Limits:** We are given that: \[ \lim_{x \to a} f(x) = \lim_{x \to a} [f(x)] ...
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