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Satement-1 : If secx + cos x =2 then (se...

Satement-1 : If `secx + cos x =2` then `(sec x)^(n)+(cos x^(n)=2`.
because
Statement-2 : If `A+B=2` and `AB=1` then `A=B=1`.

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 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

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The correct Answer is:
To solve the problem, we need to analyze the two statements given and determine their validity. ### Step 1: Analyze Statement 2 We are given that if \( A + B = 2 \) and \( AB = 1 \), then we need to show that \( A = B = 1 \). 1. Start with the equations: \[ A + B = 2 \] \[ AB = 1 \] 2. From the first equation, we can express \( B \) in terms of \( A \): \[ B = 2 - A \] 3. Substitute \( B \) in the second equation: \[ A(2 - A) = 1 \] \[ 2A - A^2 = 1 \] 4. Rearranging gives us a quadratic equation: \[ A^2 - 2A + 1 = 0 \] 5. This can be factored as: \[ (A - 1)^2 = 0 \] 6. Thus, we find: \[ A - 1 = 0 \implies A = 1 \] 7. Substituting back to find \( B \): \[ B = 2 - A = 2 - 1 = 1 \] So, we have shown that \( A = B = 1 \). Therefore, Statement 2 is true. ### Step 2: Analyze Statement 1 Now we need to show that if \( \sec x + \cos x = 2 \), then \( \sec^n x + \cos^n x = 2 \). 1. Start with the equation: \[ \sec x + \cos x = 2 \] 2. Recall that \( \sec x = \frac{1}{\cos x} \). Substitute this into the equation: \[ \frac{1}{\cos x} + \cos x = 2 \] 3. Multiply through by \( \cos x \) (assuming \( \cos x \neq 0 \)): \[ 1 + \cos^2 x = 2 \cos x \] 4. Rearranging gives us: \[ \cos^2 x - 2 \cos x + 1 = 0 \] 5. This can be factored as: \[ (\cos x - 1)^2 = 0 \] 6. Thus, we find: \[ \cos x - 1 = 0 \implies \cos x = 1 \] 7. Since \( \sec x = \frac{1}{\cos x} \), we have: \[ \sec x = \frac{1}{1} = 1 \] 8. Now we can evaluate \( \sec^n x + \cos^n x \): \[ \sec^n x + \cos^n x = 1^n + 1^n = 1 + 1 = 2 \] Thus, we have shown that \( \sec^n x + \cos^n x = 2 \). Therefore, Statement 1 is also true. ### Conclusion Both statements are true, and Statement 2 serves as a correct explanation for Statement 1.
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