If `alpha` and `beta`, `alpha` and `gamma`, `alpha` and `delta` are the roots of the equations `ax^(2)+2bx+c=0`, `2bx^(2)+cx+a=0` and `cx^(2)+ax+2b=0` respectively where `a`, `b`, `c` are positive real numbers, then `alpha+alpha^(2)` is equal to
A
`-1`
B
`1`
C
`0`
D
`abc`
Text Solution
AI Generated Solution
The correct Answer is:
To solve the problem, we need to analyze the three equations given in the question and find the value of \( \alpha + \alpha^2 \).
### Step 1: Write down the equations
The roots of the equations are given as follows:
1. \( ax^2 + 2bx + c = 0 \) (roots: \( \alpha, \beta \))
2. \( 2bx^2 + cx + a = 0 \) (roots: \( \alpha, \gamma \))
3. \( cx^2 + ax + 2b = 0 \) (roots: \( \alpha, \delta \))
### Step 2: Substitute \( \alpha \) into each equation
Since \( \alpha \) is a root of all three equations, we can substitute \( \alpha \) into each equation:
1. From the first equation:
\[
a\alpha^2 + 2b\alpha + c = 0
\]
2. From the second equation:
\[
2b\alpha^2 + c\alpha + a = 0
\]
3. From the third equation:
\[
c\alpha^2 + a\alpha + 2b = 0
\]
### Step 3: Add the three equations
Now, we add all three equations together:
\[
(a\alpha^2 + 2b\alpha + c) + (2b\alpha^2 + c\alpha + a) + (c\alpha^2 + a\alpha + 2b) = 0
\]
### Step 4: Combine like terms
Combining the terms gives us:
\[
(a + 2b + c)\alpha^2 + (2b + c + a)\alpha + (c + a + 2b) = 0
\]
### Step 5: Factor out common terms
We can factor out \( (a + 2b + c) \):
\[
(a + 2b + c)(\alpha^2 + \alpha + 1) = 0
\]
### Step 6: Analyze the factor
Since \( a, b, c \) are positive real numbers, \( a + 2b + c \) cannot be zero. Therefore, we must have:
\[
\alpha^2 + \alpha + 1 = 0
\]
### Step 7: Solve for \( \alpha + \alpha^2 \)
The equation \( \alpha^2 + \alpha + 1 = 0 \) can be rearranged to find \( \alpha + \alpha^2 \):
\[
\alpha + \alpha^2 = -1
\]
### Conclusion
Thus, the value of \( \alpha + \alpha^2 \) is:
\[
\boxed{-1}
\]
To solve the problem, we need to analyze the three equations given in the question and find the value of \( \alpha + \alpha^2 \).
### Step 1: Write down the equations
The roots of the equations are given as follows:
1. \( ax^2 + 2bx + c = 0 \) (roots: \( \alpha, \beta \))
2. \( 2bx^2 + cx + a = 0 \) (roots: \( \alpha, \gamma \))
3. \( cx^2 + ax + 2b = 0 \) (roots: \( \alpha, \delta \))
...