Rajasthan BoardEnglish MediumSTD 9MATHSNumber systems1 Mark
Question
If $\sqrt{2^\text{n}}=1024,$ then $3^{2\Big(\frac{\text{n}}{4}-4\Big)}=$
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Answer
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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