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Consider the statements : P : There ex...

Consider the statements : P : There exists some x IR such that f(x) + 2x = 2(1+x2) Q : There exists some x IR such that 2f(x) +1 = 2x(1+x) `f(x)=(1-x)^(2) sin^(2) x+x^(2)" "AA x in R` Then (A) both P and Q are true (B) P is true and Q is false (C) P is false and Q is true (D) both P and Q are false.

A

both P and Q are true

B

P is true and Q is false

C

P is false and Q is true

D

both P and Q are false

Text Solution

AI Generated Solution

The correct Answer is:
To solve the problem, we need to analyze the statements P and Q based on the function \( f(x) = (1 - x^2) \sin^2 x + x^2 \). ### Step 1: Analyze Statement P We need to check if there exists some \( x \in \mathbb{R} \) such that: \[ f(x) + 2x = 2(1 + x^2) \] Substituting \( f(x) \): \[ (1 - x^2) \sin^2 x + x^2 + 2x = 2(1 + x^2) \] This simplifies to: \[ (1 - x^2) \sin^2 x + x^2 + 2x = 2 + 2x^2 \] Rearranging gives: \[ (1 - x^2) \sin^2 x = 2 + 2x^2 - x^2 - 2x \] \[ (1 - x^2) \sin^2 x = 2 - x^2 - 2x \] Now, we can analyze the left side: \[ 1 - x^2 \geq 0 \implies x^2 \leq 1 \implies -1 \leq x \leq 1 \] The right side \( 2 - x^2 - 2x \) is a quadratic function. We can find its vertex to determine its maximum or minimum value. ### Step 2: Analyze the Quadratic Function The quadratic \( 2 - x^2 - 2x \) can be rewritten as: \[ -(x^2 + 2x - 2) \] The vertex occurs at \( x = -b/(2a) = -2/(-2) = 1 \). Evaluating at \( x = 1 \): \[ 2 - 1 - 2 = -1 \] Evaluating at \( x = -1 \): \[ 2 - 1 + 2 = 3 \] Thus, the maximum value of \( 2 - x^2 - 2x \) in the interval \( [-1, 1] \) is 3. ### Step 3: Check for Real Solutions Now we need to check if \( (1 - x^2) \sin^2 x = 2 - x^2 - 2x \) can have real solutions. Since \( (1 - x^2) \sin^2 x \) can take values from 0 to 1 (as \( \sin^2 x \) ranges from 0 to 1), it cannot equal 2 or any value greater than 1. Therefore, statement P is false. ### Step 4: Analyze Statement Q Now we check if there exists some \( x \in \mathbb{R} \) such that: \[ 2f(x) + 1 = 2x(1 + x) \] Substituting \( f(x) \): \[ 2((1 - x^2) \sin^2 x + x^2) + 1 = 2x(1 + x) \] This simplifies to: \[ 2(1 - x^2) \sin^2 x + 2x^2 + 1 = 2x + 2x^2 \] Rearranging gives: \[ 2(1 - x^2) \sin^2 x + 1 = 2x \] This implies: \[ 2(1 - x^2) \sin^2 x = 2x - 1 \] Thus, we can define: \[ h(x) = \frac{2x - 1}{1 - x^2} - 2 \sin^2 x \] We need to check if this function has a root. ### Step 5: Evaluate \( h(x) \) Evaluate \( h(0) \): \[ h(0) = \frac{2(0) - 1}{1 - 0^2} - 2 \sin^2(0) = -1 \] As \( x \) approaches 1 from the left, \( h(x) \) approaches infinity. By the Intermediate Value Theorem, since \( h(0) < 0 \) and \( h(x) \to \infty \) as \( x \to 1 \), there exists at least one solution in the interval \( (0, 1) \). ### Conclusion - Statement P is false. - Statement Q is true. Thus, the correct answer is: **(C) P is false and Q is true.**

To solve the problem, we need to analyze the statements P and Q based on the function \( f(x) = (1 - x^2) \sin^2 x + x^2 \). ### Step 1: Analyze Statement P We need to check if there exists some \( x \in \mathbb{R} \) such that: \[ f(x) + 2x = 2(1 + x^2) \] Substituting \( f(x) \): ...
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