If `a`, `b`, `c` are in geometric progresion and the roots of the equations `ax^(2)+2bx+c=0` are `alpha` and `beta` and those of `cx^(2)+2bx+a=0` are `gamma` and `delta` then
A
`alpha ne beta ne gamma ne delta`
B
`alpha ne beta` and `gamma ne delta`
C
`a alpha = a beta = c gamma = c delta`
D
`alpha=beta` , `gamma ne delta`
Text Solution
AI Generated Solution
The correct Answer is:
To solve the problem, we will analyze the given equations and the conditions provided.
### Step 1: Understand the given conditions
We know that \( a, b, c \) are in geometric progression. This means that:
\[
\frac{b^2}{ac} = 1 \quad \text{(1)}
\]
### Step 2: Analyze the roots of the first equation
The first equation is:
\[
ax^2 + 2bx + c = 0
\]
Let the roots of this equation be \( \alpha \) and \( \beta \). By Vieta's formulas, we have:
\[
\alpha + \beta = -\frac{2b}{a} \quad \text{(2)}
\]
\[
\alpha \beta = \frac{c}{a} \quad \text{(3)}
\]
### Step 3: Analyze the roots of the second equation
The second equation is:
\[
cx^2 + 2bx + a = 0
\]
Let the roots of this equation be \( \gamma \) and \( \delta \). Again, by Vieta's formulas, we have:
\[
\gamma + \delta = -\frac{2b}{c} \quad \text{(4)}
\]
\[
\gamma \delta = \frac{a}{c} \quad \text{(5)}
\]
### Step 4: Relate the roots of both equations
Since \( a, b, c \) are in geometric progression, we can express \( b \) in terms of \( a \) and \( c \):
\[
b = \sqrt{ac} \quad \text{(6)}
\]
### Step 5: Substitute \( b \) into the equations
Substituting equation (6) into equations (2) and (4):
From (2):
\[
\alpha + \beta = -\frac{2\sqrt{ac}}{a} = -\frac{2\sqrt{c}}{\sqrt{a}} \quad \text{(7)}
\]
From (4):
\[
\gamma + \delta = -\frac{2\sqrt{ac}}{c} = -\frac{2\sqrt{a}}{\sqrt{c}} \quad \text{(8)}
\]
### Step 6: Analyze the product of the roots
From equations (3) and (5):
Using (3):
\[
\alpha \beta = \frac{c}{a} \quad \text{(9)}
\]
Using (5):
\[
\gamma \delta = \frac{a}{c} \quad \text{(10)}
\]
### Step 7: Establish relationships between roots
From the properties of the equations, we can establish that:
- The roots of the second equation are the reciprocals of the roots of the first equation, i.e., \( \gamma = \frac{1}{\alpha} \) and \( \delta = \frac{1}{\beta} \).
### Step 8: Conclusion
Since \( \alpha \) and \( \beta \) are roots of the first equation and \( \gamma \) and \( \delta \) are their reciprocals, we can conclude:
\[
\alpha \beta = \frac{c}{a}, \quad \gamma \delta = \frac{a}{c}
\]
This implies:
\[
\alpha = \beta \quad \text{and} \quad \gamma = \delta \quad \text{(since they are reciprocals)}
\]
Thus, the correct answer is:
**Option C: \( \alpha = \beta \) and \( \gamma = \delta \)**.
To solve the problem, we will analyze the given equations and the conditions provided.
### Step 1: Understand the given conditions
We know that \( a, b, c \) are in geometric progression. This means that:
\[
\frac{b^2}{ac} = 1 \quad \text{(1)}
\]
...