Progressions

JEE Advanced 2015 Guidance › Algebra questions › Progressions

If three positive real numbers a, b, c are in A.P. such that abc = 4, then the minimum possible value of b is

(a) 2^3/2 (b) 2^2/3 (c)2^1/3 (d) 2^5/2

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Soumyadeep Basu ·2014-03-30 10:30:29

Use A.M.â‰¥G.M. Answer should be (b).

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Soumak Roy ·2014-03-31 09:37:50

you mean we'll use a+c2â‰¥ √ac. Then from the given relation, √ac=2√band a+c2=b. Yes this gives the answer as (b). Surprised that i couldn't figure this out !!

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Soumyadeep Basu Are, take a, b and c all together. It will give the answer directly.
Upvote·0· Reply ·2014-03-31 11:13:25
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Basic Integral Calculus Operators Symbols Matrix Cases

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∫ ∫ ∫ ∫ ∫ ∬ ∬ ∬ ∬ ∬ ∭ ∭ ∭ ∭ ∭ ⨌ ⨌ ⨌ ⨌ ⨌

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+ - × ÷ ± ∓ = ∪ ∩ ≠ ∼ ≈ ∅ ∀ ∃ ∈ ∋ ∝ ≤ ≥ ≃ ≅ ≡ < > ≪ ≫ ⊂ ∉ ⊃ ⊆ ⊇ ⇒ ⇐ ⇔ ⇒ ⇐ ⇔ ⇑ ⇓ ⇕ → ← ↔ → ← ↔ ↑ ↓ ↕ ↖ ↗ ↘ ↙ ↪ ↩ ⇀ ↼ ⇁ ↽

° ∂ ∞ α β γ δ θ λ μ ν ξ π ρ σ φ ω ε ƒ κ τ υ Γ Δ Λ Σ Π Ω

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