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Let f(x) =x^(3)-3(7-a)X^(2)-3(9-a^(2))x+...

Let f(x) =`x^(3)-3(7-a)X^(2)-3(9-a^(2))x+2`
The values of parameter a if f(x) has a negative point of local minimum are

A

`pi`

B

(-3,3)

C

`(-oo,(58)/(14))`

D

none of these

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To solve the problem, we need to determine the values of the parameter \( a \) such that the function \( f(x) = x^3 - 3(7-a)x^2 - 3(9-a^2)x + 2 \) has a negative point of local minimum. We will follow these steps: ### Step 1: Find the first derivative \( f'(x) \) The first derivative \( f'(x) \) is calculated to find the critical points where the local minima or maxima occur. \[ f'(x) = 3x^2 - 3(7-a) \cdot 2x - 3(9-a^2) \] \[ = 3x^2 - 6(7-a)x - 3(9-a^2) \] ### Step 2: Set the first derivative to zero To find the critical points, we set \( f'(x) = 0 \): \[ 3x^2 - 6(7-a)x - 3(9-a^2) = 0 \] Dividing the entire equation by 3 simplifies it: \[ x^2 - 2(7-a)x - (9-a^2) = 0 \] ### Step 3: Use the discriminant condition For the quadratic equation to have real roots, the discriminant must be non-negative: \[ D = b^2 - 4ac \geq 0 \] Here, \( a = 1 \), \( b = -2(7-a) \), and \( c = -(9-a^2) \): \[ D = [-2(7-a)]^2 - 4 \cdot 1 \cdot (-(9-a^2)) \geq 0 \] \[ = 4(7-a)^2 + 4(9-a^2) \geq 0 \] \[ = 4[(7-a)^2 + (9-a^2)] \geq 0 \] Since \( 4 \) is always positive, we can simplify to: \[ (7-a)^2 + (9-a^2) \geq 0 \] ### Step 4: Analyze the second derivative \( f''(x) \) Next, we find the second derivative \( f''(x) \) to determine the nature of the critical points: \[ f''(x) = 6x - 6(7-a) \] ### Step 5: Set the second derivative condition For a local minimum, we need \( f''(x) > 0 \): \[ 6x - 6(7-a) > 0 \] \[ x > 7-a \] ### Step 6: Establish conditions for negative local minimum Since we are looking for a negative point of local minimum, we require: \[ 7-a < 0 \implies a > 7 \] ### Step 7: Combine conditions From the discriminant condition, we have: \[ (7-a)^2 + (9-a^2) \geq 0 \] This condition is always satisfied for real values of \( a \). The critical condition we derived is \( a > 7 \). ### Conclusion The values of the parameter \( a \) such that \( f(x) \) has a negative point of local minimum are: \[ \boxed{a > 7} \]

To solve the problem, we need to determine the values of the parameter \( a \) such that the function \( f(x) = x^3 - 3(7-a)x^2 - 3(9-a^2)x + 2 \) has a negative point of local minimum. We will follow these steps: ### Step 1: Find the first derivative \( f'(x) \) The first derivative \( f'(x) \) is calculated to find the critical points where the local minima or maxima occur. \[ f'(x) = 3x^2 - 3(7-a) \cdot 2x - 3(9-a^2) \] ...
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