α మరియు β (5 + √2) x2 - (4 + √5) x + (8 + 2√5) = 0 సమీకరణం యొక్క మూలాలు అయితే , 2αβ/ (α + β) యొక్క విలువ:

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RRC Group D Previous Paper 3 (Held On: 19 Sep 2018 Shift 1)
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  1. 7
  2. 4
  3. 2
  4. 8

Answer (Detailed Solution Below)

Option 2 : 4
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సమీకరణం కోసం, ax2 + bx + c = 0, α + β = -b/a మరియు αβ = c/a

⇒ ఇక్కడ, αβ = (8 + 2√5)/(5 + √2) మరియు α + β = (4 + √5)/(5 + √2)

⇒ కావున, 2αβ/ (α + β)

⇒ 2[(8 + 2√5) / (5 + √2)] / [(4 + √5) / (5 + √2)]

⇒ 2 [(8 + 2√5) (4 - √5)] / [(4 + √5) / (4 - √5)]

⇒ 2(32 + 8√5 - 8√5 - 10)/11

⇒ 44/11 = 4
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