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If alpha and beta the roots of the equat...

If `alpha` and `beta` the roots of the equation `x^(2)-2x+3=0`, then the sum of roots of the equation having roots as `alpha^(3)-3alpha^(2)+5alpha-2` and `beta^(3)-beta^(2)+beta+5` is

A

1

B

3

C

5

D

7

Text Solution

AI Generated Solution

The correct Answer is:
To solve the given problem step-by-step, we will follow these steps: ### Step 1: Identify the roots of the quadratic equation The given quadratic equation is: \[ x^2 - 2x + 3 = 0 \] Using the quadratic formula, the roots \( \alpha \) and \( \beta \) can be calculated as: \[ \alpha, \beta = \frac{-b \pm \sqrt{b^2 - 4ac}}{2a} \] where \( a = 1, b = -2, c = 3 \). ### Step 2: Calculate the sum and product of the roots From Vieta's formulas: - The sum of the roots \( \alpha + \beta = -\frac{b}{a} = 2 \) - The product of the roots \( \alpha \beta = \frac{c}{a} = 3 \) ### Step 3: Calculate the new expressions for the roots We need to find the values of: \[ \alpha^3 - 3\alpha^2 + 5\alpha - 2 \] and \[ \beta^3 - \beta^2 + \beta + 5 \] ### Step 4: Simplify the expressions 1. **For \( \alpha \)**: \[ \alpha^3 - 3\alpha^2 + 5\alpha - 2 \] We can express \( \alpha^3 \) in terms of \( \alpha \) and \( \beta \): Using the original quadratic equation, we have: \[ \alpha^2 = 2\alpha - 3 \implies \alpha^3 = \alpha \cdot \alpha^2 = \alpha(2\alpha - 3) = 2\alpha^2 - 3\alpha \] Substituting \( \alpha^2 \): \[ = 2(2\alpha - 3) - 3\alpha = 4\alpha - 6 - 3\alpha = \alpha - 6 \] Therefore: \[ \alpha^3 - 3\alpha^2 + 5\alpha - 2 = (\alpha - 6) - 3(2\alpha - 3) + 5\alpha - 2 \] Simplifying: \[ = \alpha - 6 - 6\alpha + 9 + 5\alpha - 2 = 0 \] 2. **For \( \beta \)**: \[ \beta^3 - \beta^2 + \beta + 5 \] Similarly, we can express \( \beta^3 \): \[ \beta^3 = \beta(2\beta - 3) = 2\beta^2 - 3\beta \] Substituting \( \beta^2 \): \[ = 2(2\beta - 3) - 3\beta = 4\beta - 6 - 3\beta = \beta - 6 \] Therefore: \[ \beta^3 - \beta^2 + \beta + 5 = (\beta - 6) - (2\beta - 3) + \beta + 5 \] Simplifying: \[ = \beta - 6 - 2\beta + 3 + \beta + 5 = 2 \] ### Step 5: Calculate the sum of the new roots Now we have: - The first root \( \alpha^3 - 3\alpha^2 + 5\alpha - 2 = 0 \) - The second root \( \beta^3 - \beta^2 + \beta + 5 = 2 \) Thus, the sum of the new roots is: \[ 0 + 2 = 2 \] ### Final Answer The sum of the roots of the new equation is: \[ \boxed{2} \]
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