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Given |px^(2) + qx + r| le |Px^(2) + Qx ...

Given `|px^(2) + qx + r| le |Px^(2) + Qx + R|AA x in R` and `d=q^(2) - 4pr gt 0` and `D =Q^(2) -4PR gt 0`
Which of the following must be ture ?

A

(a) `|p| ge |P|`

B

(b) `|p| le |P|`

C

(c) `|p| = |P|`

D

(d) All of these

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The correct Answer is:
To solve the problem, we need to analyze the given inequalities and the conditions provided. ### Step-by-Step Solution: 1. **Understanding the Given Inequality**: We have the inequality: \[ |px^2 + qx + r| \leq |Px^2 + Qx + R| \quad \forall x \in \mathbb{R} \] This means that the quadratic polynomial \(px^2 + qx + r\) is always less than or equal to the polynomial \(Px^2 + Qx + R\) in absolute value for all real numbers \(x\). 2. **Discriminants**: We are given that: \[ d = q^2 - 4pr > 0 \quad \text{and} \quad D = Q^2 - 4PR > 0 \] This indicates that both quadratics have real and distinct roots. 3. **Graphical Interpretation**: The graphs of both quadratics will be parabolas. Since \(d > 0\) and \(D > 0\), both parabolas will intersect the x-axis at two distinct points. 4. **Roots of the Quadratics**: Let the roots of \(px^2 + qx + r\) be \(\alpha\) and \(\beta\), and the roots of \(Px^2 + Qx + R\) also be \(\alpha\) and \(\beta\). Since the inequality holds for all \(x\), the two polynomials must be equal at their roots. 5. **Factoring the Quadratics**: We can express the quadratics in factored form: \[ px^2 + qx + r = p(x - \alpha)(x - \beta) \] \[ Px^2 + Qx + R = P(x - \alpha)(x - \beta) \] 6. **Analyzing the Inequality**: The given inequality can be simplified: \[ |p(x - \alpha)(x - \beta)| \leq |P(x - \alpha)(x - \beta)| \] Since \((x - \alpha)(x - \beta)\) is common in both sides, we can cancel it out, assuming it is not zero (which is valid except at the roots): \[ |p| \leq |P| \] 7. **Conclusion**: From the analysis, we conclude that: \[ |p| \leq |P| \] This means that the absolute value of \(p\) must be less than or equal to the absolute value of \(P\). ### Final Answer: Thus, the statement that must be true is: \[ |p| \leq |P| \]

To solve the problem, we need to analyze the given inequalities and the conditions provided. ### Step-by-Step Solution: 1. **Understanding the Given Inequality**: We have the inequality: \[ |px^2 + qx + r| \leq |Px^2 + Qx + R| \quad \forall x \in \mathbb{R} ...
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