Question
If $\sqrt{2^\text{n}}=1024,$ then $3^{2\Big(\frac{\text{n}}{4}-4\Big)}=$

Answer

  1. 9
    Solution:
    We have to find $3^{2\Big(\frac{\text{n}}{4}-4\Big)}$
    Given $\sqrt{2^\text{n}}=1024$
    $\sqrt{2^\text{n}}=2^\text{10}$
    $2^{\text{n}\times\frac{1}{2}}$
    Equating powers of rational exponents we get
    $\text{n}\times\frac{1}{2}=10$
    $\text{n}=10\times2$
    $\text{n}=20$
    Substituting in $3^{2\Big(\frac{\text{n}}{4}-4\Big)}$ we get
    $3^{2\Big(\frac{\text{n}}{4}-4\Big)}=3^{2\Big(\frac{20}{4}-4\Big)}$
    $=3^{2(5-4)}$
    $=3^{2\times1}$
    $=9$
    Hence the correct choice is b.

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