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Statement-1:For any n in N, we have in...

Statement-1:For any `n in N`, we have
`int_(0)^(npi) |(sinx)/(x)|dx ge (2)/(pi)(1+(1)/(2)+(1)/(3)+....+(1)/(n))`
Statement-2:`(sin x)/(x)ge(2)/(pi)"on"(0,(pi)/(2))`

A

Statement-1 is true, Statement-2 is True,Statement-2 is a correct explanation for Statement-1.

B

Statement-1 is True, Statement-2 is not a correct explanation for Statement-1.

C

Statement-1 is True, Statement-2 is False.

D

Statement-1 is False, Statement-2 is True.

Text Solution

AI Generated Solution

The correct Answer is:
To solve the problem, we need to analyze both statements and prove their validity step by step. ### Step 1: Understanding Statement 1 We need to prove that: \[ \int_0^{n\pi} \left| \frac{\sin x}{x} \right| dx \geq \frac{2}{\pi} \left( 1 + \frac{1}{2} + \frac{1}{3} + \ldots + \frac{1}{n} \right) \] ### Step 2: Breaking Down the Integral Let's denote the integral as: \[ I = \int_0^{n\pi} \left| \frac{\sin x}{x} \right| dx \] The function \(\frac{\sin x}{x}\) is positive for \(x > 0\), so we can drop the absolute value: \[ I = \int_0^{n\pi} \frac{\sin x}{x} dx \] ### Step 3: Using the Properties of the Sine Function The function \(\sin x\) has a period of \(2\pi\). Therefore, we can break the integral into \(n\) intervals of length \(\pi\): \[ I = \sum_{r=0}^{n-1} \int_{r\pi}^{(r+1)\pi} \frac{\sin x}{x} dx \] ### Step 4: Change of Variables For each interval, we can perform a change of variables: Let \(x = r\pi + u\), where \(u\) varies from \(0\) to \(\pi\) as \(x\) varies from \(r\pi\) to \((r+1)\pi\). Then: \[ I = \sum_{r=0}^{n-1} \int_0^{\pi} \frac{\sin(r\pi + u)}{r\pi + u} du \] Using the property \(\sin(r\pi + u) = (-1)^r \sin u\), we can write: \[ I = \sum_{r=0}^{n-1} (-1)^r \int_0^{\pi} \frac{\sin u}{r\pi + u} du \] ### Step 5: Estimating the Integral We can estimate the integral \(\int_0^{\pi} \frac{\sin u}{r\pi + u} du\). Since \(\sin u\) is bounded between \(0\) and \(1\), we can say: \[ \int_0^{\pi} \frac{\sin u}{r\pi + u} du \geq \int_0^{\pi} \frac{2}{\pi} \cdot \frac{\sin u}{u} du \] Thus, we can conclude: \[ I \geq \frac{2}{\pi} \sum_{r=1}^{n} \left( \int_0^{\pi} \frac{1}{r} du \right) = \frac{2}{\pi} \sum_{r=1}^{n} \frac{\pi}{r} = \frac{2}{\pi} \left( 1 + \frac{1}{2} + \frac{1}{3} + \ldots + \frac{1}{n} \right) \] ### Step 6: Conclusion for Statement 1 Thus, we have shown that: \[ I \geq \frac{2}{\pi} \left( 1 + \frac{1}{2} + \frac{1}{3} + \ldots + \frac{1}{n} \right) \] which confirms that Statement 1 is true. ### Step 7: Understanding Statement 2 Statement 2 claims that: \[ \frac{\sin x}{x} \geq \frac{2}{\pi} \quad \text{for } x \in (0, \frac{\pi}{2}) \] To prove this, we can analyze the function \(\frac{\sin x}{x}\) on the interval \((0, \frac{\pi}{2})\). ### Step 8: Analyzing the Function The function \(\frac{\sin x}{x}\) is known to be decreasing on the interval \((0, \frac{\pi}{2})\). At \(x = \frac{\pi}{2}\): \[ \frac{\sin(\frac{\pi}{2})}{\frac{\pi}{2}} = \frac{2}{\pi} \] Since the function is decreasing, it follows that: \[ \frac{\sin x}{x} \geq \frac{2}{\pi} \quad \text{for all } x \in (0, \frac{\pi}{2}) \] Thus, Statement 2 is also true. ### Final Conclusion Both statements are true, and Statement 2 serves as a correct explanation for Statement 1. ---

To solve the problem, we need to analyze both statements and prove their validity step by step. ### Step 1: Understanding Statement 1 We need to prove that: \[ \int_0^{n\pi} \left| \frac{\sin x}{x} \right| dx \geq \frac{2}{\pi} \left( 1 + \frac{1}{2} + \frac{1}{3} + \ldots + \frac{1}{n} \right) \] ...
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