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Consider a DeltaABC satisfying 2aSin^(2)...

Consider a `DeltaABC` satisfying `2aSin^(2)((C)/(2))+2cSin^(2)((A)/(2))=2a+2c-3b`
The sides of the triangle are in

A

A. GP

B

B. AP

C

C. HP

D

D. None

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The correct Answer is:
To solve the problem, we need to analyze the given equation and derive the relationship between the sides of triangle \( \Delta ABC \). ### Step-by-Step Solution: 1. **Write the Given Equation**: We start with the equation provided: \[ 2a \sin^2\left(\frac{C}{2}\right) + 2c \sin^2\left(\frac{A}{2}\right) = 2a + 2c - 3b \] 2. **Express \( \sin^2\left(\frac{C}{2}\right) \) and \( \sin^2\left(\frac{A}{2}\right) \)**: Using the formula for \( \sin\left(\frac{C}{2}\right) \) and \( \sin\left(\frac{A}{2}\right) \): \[ \sin\left(\frac{C}{2}\right) = \sqrt{\frac{s - a}{s}} \quad \text{and} \quad \sin\left(\frac{A}{2}\right) = \sqrt{\frac{s - b}{s}} \] where \( s = \frac{a + b + c}{2} \). 3. **Substituting into the Equation**: Substitute these expressions into the original equation: \[ 2a \left(\frac{s - a}{s}\right) + 2c \left(\frac{s - b}{s}\right) = 2a + 2c - 3b \] 4. **Simplifying the Left Side**: The left side becomes: \[ \frac{2a(s - a) + 2c(s - b)}{s} = 2a + 2c - 3b \] Expanding this gives: \[ \frac{2as - 2a^2 + 2cs - 2bc}{s} = 2a + 2c - 3b \] 5. **Clearing the Denominator**: Multiply through by \( s \) to eliminate the fraction: \[ 2as - 2a^2 + 2cs - 2bc = s(2a + 2c - 3b) \] 6. **Rearranging the Equation**: Rearranging gives: \[ 2as + 2cs - 2bc = 2as + 2cs - 3bs \] Simplifying leads to: \[ 2bc = 3bs \] 7. **Dividing by \( b \)** (assuming \( b \neq 0 \)): \[ 2c = 3s \] 8. **Substituting \( s \)**: Recall \( s = \frac{a + b + c}{2} \): \[ 2c = 3 \left(\frac{a + b + c}{2}\right) \] Simplifying gives: \[ 4c = 3(a + b + c) \] 9. **Rearranging**: Rearranging leads to: \[ 4c - 3c = 3a + 3b \implies c = 3a + 3b \] 10. **Conclusion**: We find that \( 2b = a + c \), which indicates that the sides of triangle \( \Delta ABC \) are in Arithmetic Progression (AP). ### Final Answer: The sides of the triangle are in **Arithmetic Progression (AP)**.
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