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Statement -1: Let f(x) be a function sat...

Statement -1: Let f(x) be a function satisfying `f(x-1)+f(x+1)=sqrt(2)f(x)` for all ` x in R ` . Then f(x) is periodic with period 8. Statement-2: For every natural number n there exists a periodic functions with period n.

A

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

B

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

C

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

D

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

Text Solution

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The correct Answer is:
To solve the problem, we need to analyze the two statements provided. ### Step 1: Analyze Statement 1 We have the functional equation: \[ f(x-1) + f(x+1) = \sqrt{2} f(x) \] for all \( x \in \mathbb{R} \). We need to determine if \( f(x) \) is periodic with period 8. ### Step 2: Substitute Values Let's substitute \( x \) with \( x + 1 \) in the original equation: \[ f((x + 1) - 1) + f((x + 1) + 1) = \sqrt{2} f(x + 1) \] This simplifies to: \[ f(x) + f(x + 2) = \sqrt{2} f(x + 1) \] (Equation 2) Now, let's substitute \( x \) with \( x - 1 \): \[ f((x - 1) - 1) + f((x - 1) + 1) = \sqrt{2} f(x - 1) \] This simplifies to: \[ f(x - 2) + f(x) = \sqrt{2} f(x - 1) \] (Equation 3) ### Step 3: Combine Equations Now we have three equations: 1. \( f(x-1) + f(x+1) = \sqrt{2} f(x) \) (Original) 2. \( f(x) + f(x+2) = \sqrt{2} f(x + 1) \) (Equation 2) 3. \( f(x - 2) + f(x) = \sqrt{2} f(x - 1) \) (Equation 3) Let's add Equations 2 and 3: \[ (f(x) + f(x + 2)) + (f(x - 2) + f(x)) = \sqrt{2} f(x + 1) + \sqrt{2} f(x - 1) \] This simplifies to: \[ 2f(x) + f(x + 2) + f(x - 2) = \sqrt{2} (f(x + 1) + f(x - 1)) \] ### Step 4: Rearranging From the original equation, we can express \( f(x + 1) + f(x - 1) \) in terms of \( f(x) \): \[ f(x + 1) + f(x - 1) = \sqrt{2} f(x) \] Substituting this back into our combined equation gives us: \[ 2f(x) + f(x + 2) + f(x - 2) = \sqrt{2} \cdot \sqrt{2} f(x) \] \[ 2f(x) + f(x + 2) + f(x - 2) = 2f(x) \] Thus, we have: \[ f(x + 2) + f(x - 2) = 0 \] This implies: \[ f(x + 2) = -f(x - 2) \] ### Step 5: Finding Periodicity Continuing this process, we can find that: - \( f(x + 4) = -f(x) \) - \( f(x + 8) = f(x) \) This shows that \( f(x) \) is periodic with period 8. ### Conclusion for Statement 1 Thus, Statement 1 is true: \( f(x) \) is periodic with period 8. ### Step 6: Analyze Statement 2 Statement 2 states that for every natural number \( n \), there exists a periodic function with period \( n \). This is indeed true since we can construct functions like \( f(x) = \sin\left(\frac{2\pi}{n} x\right) \) which has period \( n \). ### Final Conclusion Both statements are true, but Statement 2 does not explain Statement 1. Therefore, the correct conclusion is that both statements are true, but Statement 2 is not an explanation for Statement 1.

To solve the problem, we need to analyze the two statements provided. ### Step 1: Analyze Statement 1 We have the functional equation: \[ f(x-1) + f(x+1) = \sqrt{2} f(x) \] for all \( x \in \mathbb{R} \). We need to determine if \( f(x) \) is periodic with period 8. ### Step 2: Substitute Values ...
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