Related Formula
Sum of coefficients = 0 x = 1 is a root.$$\text{Sum of coefficients} = 0 \implies x = 1 \text{ is a root.}$$
Core Logic
Given f(x) = (a + b - 2c)x² + (b + c - 2a)x + (c + a - 2b) = 0$f(x) = (a + b - 2c)x^2 + (b + c - 2a)x + (c + a - 2b) = 0$.
Substituting x = 1$x = 1$:
f(1) = a + b - 2c + b + c - 2a + c + a - 2b = 0$$f(1) = a + b - 2c + b + c - 2a + c + a - 2b = 0$$
Thus, one root is 1$1$. Let the other root be α$\alpha$.
Step 1: Find the other root
Product of roots = (c + a - 2b)/(a + b - 2c)$\frac{c + a - 2b}{a + b - 2c}$.
Since one root is 1$1$, we have:
α · 1 = (c + a - 2b)/(a + b - 2c)$$\alpha \cdot 1 = \frac{c + a - 2b}{a + b - 2c}$$
α = (c + a - 2b)/(a + b - 2c)$$\alpha = \frac{c + a - 2b}{a + b - 2c}$$
Step 2: Analyze Statement (I)
If -1 < α < 0$-1 < \alpha < 0$:
-1 < (c + a - 2b)/(a + b - 2c) < 0$$-1 < \frac{c + a - 2b}{a + b - 2c} < 0$$
This implies b > (a + c)/(2)$b > \frac{a + c}{2}$ and b + c < 2a$b + c < 2a$.
Therefore, b$b$ cannot be the Geometric Mean of a$a$ and c$c$. Statement (I) is true.
Step 3: Analyze Statement (II)
If 0 < α < 1$0 < \alpha < 1$:
0 < (c + a - 2b)/(a + b - 2c) < 1$$0 < \frac{c + a - 2b}{a + b - 2c} < 1$$
This gives b > c$b > c$ and b < (a + c)/(2)$b < \frac{a + c}{2}$.
Therefore, b$b$ may be the Geometric Mean between a$a$ and c$c$. Statement (II) is true.
Pattern Recognition
When coefficients in a quadratic equation are cyclic and sum to 0, one root is always 1$1$. The other root is directly c/a$c/a$.
Chapter Mix
Class 11 Maths: Quadratic Equations
Class 11 Maths: Sequences and Series