MCQ
The value of $(\sqrt{5}+1)^{5}-(\sqrt{5}-1)^{5} $ is:
  • A
    $252$
  • $352$
  • C
    $452$
  • D
    $532$

Answer

Correct option: B.
$352$
Given, $(\sqrt{5}+1)^{5}-(\sqrt{5}-1)^{5} $
$=(\sqrt{5}+1)^{5}-(\sqrt{5}-1)^{5} $
The even terms will get eliminated.
Hence, we get
$2\left[{ }^5 \mathrm{C}_0+{ }^5 \mathrm{C}_2 5+{ }^5 \mathrm{C}_4 5^2\right]$
$= 2 [1 + 50 + 125]$
$= 2 [176]$
$= 352.$

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