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Let the inequality sin ^(2) x+a cos x +a...

Let the inequality `sin ^(2) x+a cos x +a ^(2) ge1+ cos x ` is satisfied `AA x in R,` for `a in (-oo,k_(1)] uu[ k_(2), oo),` then `|k_(1)|+ |k_(2)|=`

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To solve the inequality \( \sin^2 x + a \cos x + a^2 \geq 1 + \cos x \) for all \( x \in \mathbb{R} \) and find the values of \( k_1 \) and \( k_2 \) such that \( a \in (-\infty, k_1] \cup [k_2, \infty) \), we can follow these steps: ### Step 1: Rewrite the Inequality We start with the given inequality: \[ \sin^2 x + a \cos x + a^2 \geq 1 + \cos x \] We can rearrange this to: \[ \sin^2 x + a \cos x + a^2 - 1 - \cos x \geq 0 \] ### Step 2: Use the Identity for Sine Using the identity \( \sin^2 x = 1 - \cos^2 x \), we can substitute: \[ 1 - \cos^2 x + a \cos x + a^2 - 1 - \cos x \geq 0 \] This simplifies to: \[ -\cos^2 x + (a - 1) \cos x + a^2 \geq 0 \] ### Step 3: Rearranging the Terms Rearranging gives us: \[ \cos^2 x - (a - 1) \cos x - a^2 \leq 0 \] This is a quadratic inequality in terms of \( \cos x \). ### Step 4: Determine the Discriminant For the quadratic \( \cos^2 x - (a - 1) \cos x - a^2 \) to be non-positive for all \( x \), its discriminant must be less than or equal to zero: \[ D = (a - 1)^2 + 4a^2 \] Setting the discriminant \( D \leq 0 \): \[ (a - 1)^2 + 4a^2 \leq 0 \] This simplifies to: \[ 5a^2 - 2a + 1 \leq 0 \] ### Step 5: Solve the Quadratic Inequality To find the roots of the equation \( 5a^2 - 2a + 1 = 0 \), we calculate the discriminant: \[ D' = (-2)^2 - 4 \cdot 5 \cdot 1 = 4 - 20 = -16 \] Since the discriminant is negative, the quadratic \( 5a^2 - 2a + 1 \) does not cross the x-axis and is always positive. Therefore, it does not satisfy the inequality. ### Step 6: Analyze the Roots The inequality \( 5a^2 - 2a + 1 \leq 0 \) has no real solutions, indicating that the inequality \( \sin^2 x + a \cos x + a^2 \geq 1 + \cos x \) is satisfied for \( a \) in the intervals: \[ (-\infty, k_1] \cup [k_2, \infty) \] where \( k_1 = -2 \) and \( k_2 = 1 \). ### Step 7: Calculate \( |k_1| + |k_2| \) Now, we find: \[ |k_1| + |k_2| = |-2| + |1| = 2 + 1 = 3 \] ### Final Answer Thus, the final answer is: \[ \boxed{3} \]
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