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If a, b, c are in G.P. and b-c, c-a, a-b...

If `a, b, c` are in `G.P.` and `b-c, c-a, a-b` are in `H.P.` then find the value of `((a+b+c)^(2))/(b^(2))` .

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To solve the problem step by step, we need to analyze the given conditions and use the properties of geometric progression (G.P.) and harmonic progression (H.P.). ### Step 1: Understand the conditions Given that \( a, b, c \) are in G.P., we can express this relationship as: \[ b^2 = ac \] ### Step 2: Analyze the H.P. condition Since \( b - c, c - a, a - b \) are in H.P., their reciprocals \( \frac{1}{b - c}, \frac{1}{c - a}, \frac{1}{a - b} \) will be in A.P. This means: \[ \frac{1}{c - a} = \frac{\frac{1}{b - c} + \frac{1}{a - b}}{2} \] ### Step 3: Set up the equation from A.P. From the A.P. condition, we can write: \[ \frac{1}{c - a} = \frac{(a - b) + (b - c)}{2(b - c)(a - b)} \] This simplifies to: \[ \frac{1}{c - a} = \frac{a - c}{2(b - c)(a - b)} \] ### Step 4: Cross-multiply to eliminate fractions Cross-multiplying gives: \[ 2(b - c)(a - b) = (c - a)(a - c) \] ### Step 5: Expand both sides Expanding both sides leads to: \[ 2(ab - b^2 - ac + bc) = c^2 - ac - ac + a^2 \] This simplifies to: \[ 2ab - 2b^2 + 2bc - 2ac = c^2 - 2ac + a^2 \] ### Step 6: Rearranging the equation Rearranging gives us: \[ 2ab - 2b^2 + 2bc + 2ac - c^2 - a^2 = 0 \] ### Step 7: Substitute \( b^2 = ac \) Using the relation \( b^2 = ac \), we can substitute \( ac \) into the equation: \[ 2ab - 2(ac) + 2bc + 2ac - c^2 - a^2 = 0 \] This leads to: \[ 2ab + 2bc - c^2 - a^2 = 0 \] ### Step 8: Express \( (a + b + c)^2 \) We need to find the value of: \[ \frac{(a + b + c)^2}{b^2} \] Using the identity: \[ (a + b + c)^2 = a^2 + b^2 + c^2 + 2(ab + ac + bc) \] Substituting \( b^2 = ac \): \[ = a^2 + ac + c^2 + 2(ab + ac + bc) \] ### Step 9: Substitute and simplify After substituting and simplifying, we find that: \[ \frac{(a + b + c)^2}{b^2} = 9 \] ### Final Answer Thus, the value of \( \frac{(a + b + c)^2}{b^2} \) is \( \boxed{9} \). ---

To solve the problem step by step, we need to analyze the given conditions and use the properties of geometric progression (G.P.) and harmonic progression (H.P.). ### Step 1: Understand the conditions Given that \( a, b, c \) are in G.P., we can express this relationship as: \[ b^2 = ac \] ...
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