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If f(x)=int(-2)^(x)(t^(4)-bt^(3)+(b+1)t^...

If `f(x)=int_(-2)^(x)(t^(4)-bt^(3)+(b+1)t^(2)-bt+b)dt` strictly increases `AAxepsilonR` then no. of integers in range of `b` is

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To solve the problem, we need to analyze the function \( f(x) = \int_{-2}^{x} (t^4 - bt^3 + (b+1)t^2 - bt + b) \, dt \) and determine the conditions under which this function is strictly increasing. ### Step-by-Step Solution: 1. **Understanding Strictly Increasing Function**: A function \( f(x) \) is strictly increasing if its derivative \( f'(x) > 0 \) for all \( x \in \mathbb{R} \). 2. **Using the Leibniz Rule**: To find \( f'(x) \), we apply the Leibniz rule for differentiation under the integral sign: \[ f'(x) = \frac{d}{dx} \int_{-2}^{x} (t^4 - bt^3 + (b+1)t^2 - bt + b) \, dt = (x^4 - bx^3 + (b+1)x^2 - bx + b) \] 3. **Setting the Derivative Greater Than Zero**: We need to ensure that: \[ x^4 - bx^3 + (b+1)x^2 - bx + b > 0 \quad \forall x \in \mathbb{R} \] 4. **Analyzing the Polynomial**: The expression can be rearranged as: \[ x^4 + (1-b)x^2 + b - bx^3 - bx > 0 \] We can factor out the common terms: \[ = x^2(x^2 + 1) - bx(x^2 + 1) + b \] This simplifies to: \[ (x^2 - bx + b)(x^2 + 1) > 0 \] 5. **Finding Conditions for Positivity**: Since \( x^2 + 1 > 0 \) for all \( x \), we only need to ensure: \[ x^2 - bx + b > 0 \quad \forall x \in \mathbb{R} \] This is a quadratic in \( x \), and for it to be positive for all \( x \), its discriminant must be less than zero: \[ D = b^2 - 4b < 0 \] Simplifying gives: \[ b(b - 4) < 0 \] 6. **Finding the Range of \( b \)**: The inequality \( b(b - 4) < 0 \) implies: - \( b < 0 \) or \( b > 4 \) gives positive values. - \( 0 < b < 4 \) gives negative values. Thus, \( b \) must lie in the interval: \[ 0 < b < 4 \] 7. **Counting the Integer Values**: The integers in the range \( (0, 4) \) are \( 1, 2, 3 \). Therefore, there are **3 integers** in this range. ### Final Answer: The number of integers in the range of \( b \) is **3**.

To solve the problem, we need to analyze the function \( f(x) = \int_{-2}^{x} (t^4 - bt^3 + (b+1)t^2 - bt + b) \, dt \) and determine the conditions under which this function is strictly increasing. ### Step-by-Step Solution: 1. **Understanding Strictly Increasing Function**: A function \( f(x) \) is strictly increasing if its derivative \( f'(x) > 0 \) for all \( x \in \mathbb{R} \). 2. **Using the Leibniz Rule**: ...
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