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Let alpha + beta = 1, 2 alpha^(2) + 2bet...

Let `alpha + beta = 1, 2 alpha^(2) + 2beta^(2) = 1 and f(x)` be a continuous function such that `f(2 + x) + f(x) = 2` for all `x in [0, 2] and p = int_(0)^(4) f(x) dx - 4, q = (alpha)/(beta)`. Then, find the least positive integral value of 'a' for which the equation `ax^(2) - bx + c = 0` has both roots lying between p and q, where `a, b, c in N`.

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To solve the problem step by step, we will start by analyzing the given equations and conditions. ### Step 1: Analyze the given equations We have: 1. \( \alpha + \beta = 1 \) 2. \( 2\alpha^2 + 2\beta^2 = 1 \) From the first equation, we can express \( \beta \) in terms of \( \alpha \): \[ \beta = 1 - \alpha \] ### Step 2: Substitute \(\beta\) in the second equation Substituting \(\beta\) into the second equation: \[ 2\alpha^2 + 2(1 - \alpha)^2 = 1 \] Expanding the equation: \[ 2\alpha^2 + 2(1 - 2\alpha + \alpha^2) = 1 \] \[ 2\alpha^2 + 2 - 4\alpha + 2\alpha^2 = 1 \] Combining like terms: \[ 4\alpha^2 - 4\alpha + 2 = 1 \] \[ 4\alpha^2 - 4\alpha + 1 = 0 \] ### Step 3: Solve the quadratic equation for \(\alpha\) Using the quadratic formula \( \alpha = \frac{-b \pm \sqrt{b^2 - 4ac}}{2a} \): Here, \( a = 4, b = -4, c = 1 \): \[ \alpha = \frac{4 \pm \sqrt{(-4)^2 - 4 \cdot 4 \cdot 1}}{2 \cdot 4} \] \[ \alpha = \frac{4 \pm \sqrt{16 - 16}}{8} \] \[ \alpha = \frac{4}{8} = \frac{1}{2} \] ### Step 4: Find \(\beta\) Since \( \alpha + \beta = 1 \): \[ \beta = 1 - \frac{1}{2} = \frac{1}{2} \] ### Step 5: Calculate \( q \) Now, we can find \( q = \frac{\alpha}{\beta} \): \[ q = \frac{\frac{1}{2}}{\frac{1}{2}} = 1 \] ### Step 6: Analyze the function \( f(x) \) We have the condition: \[ f(2 + x) + f(x) = 2 \quad \text{for all } x \in [0, 2] \] Let’s check \( x = 0 \): \[ f(2) + f(0) = 2 \] Let’s check \( x = 2 \): \[ f(4) + f(2) = 2 \] ### Step 7: Find \( p \) We need to compute \( p = \int_0^4 f(x) \, dx - 4 \). Using the functional equation, we can find \( f(x) \) is constant. Assume \( f(x) = 1 \) (since \( f(x) \) must be continuous and satisfy the equation): \[ \int_0^4 f(x) \, dx = \int_0^4 1 \, dx = 4 \] Thus, \[ p = 4 - 4 = 0 \] ### Step 8: Set up the quadratic equation We need to find the least positive integral value of \( a \) such that the equation \( ax^2 - bx + c = 0 \) has both roots between \( p \) and \( q \): \[ p = 0, \quad q = 1 \] Thus, we need both roots to lie in the interval \( (0, 1) \). ### Step 9: Conditions for the roots For the roots to lie in \( (0, 1) \): 1. The sum of the roots \( \frac{b}{a} < 2 \) (since both roots are less than 1). 2. The product of the roots \( \frac{c}{a} > 0 \) (since both roots are positive). ### Step 10: Choose values for \( a, b, c \) Let’s choose \( a = 1 \): 1. Then \( b < 2 \) implies \( b = 1 \). 2. \( c > 0 \) implies \( c = 1 \). Thus, the quadratic equation becomes: \[ x^2 - x + 1 = 0 \] The discriminant \( b^2 - 4ac = 1 - 4 < 0 \) does not yield real roots. ### Step 11: Increase \( a \) Let’s try \( a = 2 \): 1. Then \( b < 4 \) implies \( b = 3 \). 2. \( c > 0 \) implies \( c = 1 \). The quadratic equation becomes: \[ 2x^2 - 3x + 1 = 0 \] The discriminant: \[ (-3)^2 - 4 \cdot 2 \cdot 1 = 9 - 8 = 1 \geq 0 \] The roots are: \[ x = \frac{3 \pm 1}{4} = 1 \quad \text{and} \quad \frac{2}{4} = \frac{1}{2} \] Both roots \( \frac{1}{2} \) and \( 1 \) lie in \( (0, 1) \). ### Conclusion The least positive integral value of \( a \) for which the equation has both roots lying between \( p \) and \( q \) is: \[ \boxed{2} \]
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