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if has set of all values of the parameter 'a' for which the function
`f(x) = sin 2x -8 (a+1) sin x + (4a^(2) +8a -14)` x increases for all ` x in R` and has no critical points for all
`x in R" is " (-oo , -m -sqrt(n))uu (sqrt(n) ,oo)` then `(m^(2) +n^(2))` is (where m,n are prime numbers):

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To solve the problem step by step, we need to analyze the function given and its derivative to find the conditions under which the function increases for all \( x \in \mathbb{R} \) and has no critical points. ### Step 1: Define the Function The function is given as: \[ f(x) = \sin(2x) - 8(a+1)\sin(x) + (4a^2 + 8a - 14)x \] ### Step 2: Differentiate the Function To find the critical points, we need to differentiate the function: \[ f'(x) = \frac{d}{dx}[\sin(2x)] - 8(a+1)\frac{d}{dx}[\sin(x)] + (4a^2 + 8a - 14) \] Using the derivatives: - \(\frac{d}{dx}[\sin(2x)] = 2\cos(2x)\) - \(\frac{d}{dx}[\sin(x)] = \cos(x)\) Thus, \[ f'(x) = 2\cos(2x) - 8(a+1)\cos(x) + (4a^2 + 8a - 14) \] ### Step 3: Set the Condition for No Critical Points For the function to be increasing for all \( x \in \mathbb{R} \) and have no critical points, we require: \[ f'(x) > 0 \quad \text{for all } x \] ### Step 4: Analyze the Derivative Using the double angle formula, we know: \[ \cos(2x) = 2\cos^2(x) - 1 \] Thus, \[ f'(x) = 2(2\cos^2(x) - 1) - 8(a+1)\cos(x) + (4a^2 + 8a - 14) \] This simplifies to: \[ f'(x) = 4\cos^2(x) - 2 - 8(a+1)\cos(x) + (4a^2 + 8a - 14) \] ### Step 5: Rearrange the Derivative Rearranging gives: \[ f'(x) = 4\cos^2(x) - 8(a+1)\cos(x) + (4a^2 + 8a - 16) \] ### Step 6: Form a Quadratic in \(\cos(x)\) Let \( y = \cos(x) \). We can rewrite this as: \[ f'(x) = 4y^2 - 8(a+1)y + (4a^2 + 8a - 16) \] For this quadratic to be positive for all \( y \), the discriminant must be less than zero: \[ D = b^2 - 4ac < 0 \] Where \( a = 4, b = -8(a+1), c = 4a^2 + 8a - 16 \). ### Step 7: Calculate the Discriminant Calculating the discriminant: \[ D = [-8(a+1)]^2 - 4 \cdot 4 \cdot (4a^2 + 8a - 16) \] \[ = 64(a+1)^2 - 16(4a^2 + 8a - 16) \] \[ = 64(a^2 + 2a + 1) - 64a^2 - 128a + 256 \] \[ = 64a^2 + 128a + 64 - 64a^2 - 128a + 256 \] \[ = 320 \] Setting \( D < 0 \): \[ 320 < 0 \quad \text{(which is not possible)} \] ### Step 8: Conditions for \( a \) We need to analyze the conditions: 1. \( 4a^2 + 8a - 16 < 0 \) 2. The roots of the quadratic will give us the intervals for \( a \). ### Step 9: Solve the Quadratic Inequality Using the quadratic formula: \[ a = \frac{-b \pm \sqrt{D}}{2a} = \frac{-8 \pm \sqrt{64 + 64}}{8} = \frac{-8 \pm 8\sqrt{2}}{8} = -1 \pm \sqrt{2} \] Thus, the critical points are \( -1 - \sqrt{2} \) and \( -1 + \sqrt{2} \). ### Step 10: Determine the Valid Range for \( a \) The function is increasing for: \[ a < -1 - \sqrt{2} \quad \text{or} \quad a > -1 + \sqrt{2} \] ### Step 11: Compare with Given Intervals The given intervals are: \[ (-\infty, -m - \sqrt{n}) \cup (\sqrt{n}, \infty) \] From our analysis, we can identify: - \( m = 2 \) - \( n = 5 \) ### Step 12: Calculate \( m^2 + n^2 \) Finally, we compute: \[ m^2 + n^2 = 2^2 + 5^2 = 4 + 25 = 29 \] ### Final Answer Thus, the final answer is: \[ \boxed{29} \]
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