The exponential form of $\sqrt{\sqrt{2} \times \sqrt{3}}$ is
Aptitude
Surds and Indices
Difficulty: Easy
Choose an option
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A$6$
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B$6^{\frac{1}{2}}$
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C$6^{\frac{1}{3}}$
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D$6^{\frac{1}{4}}$
Answer
Correct Answer: $6^{\frac{1}{4}}$
Explanation
### Concept & Formula
To find the exponential form of nested surds, you must apply the product rule for radicals and then convert the radical notation into fractional exponents.
$$\sqrt{a} \times \sqrt{b} = \sqrt{a \times b}$$
$$\sqrt[n]{x} = x^{\frac{1}{n}}$$
### Step-by-Step Solution
* **Given:**
The expression is $\sqrt{\sqrt{2} \times \sqrt{3}}$.
* **Calculation / Deduction:**
1. First, simplify the innermost part of the expression by multiplying the two square roots:
$$\sqrt{2} \times \sqrt{3} = \sqrt{2 \times 3} = \sqrt{6}$$
2. Substitute this back into the original expression:
$$\sqrt{\sqrt{6}}$$
3. Convert the inner square root to a fractional exponent:
$$\sqrt{6^{\frac{1}{2}}}$$
4. Convert the outer square root to a fractional exponent:
$$(6^{\frac{1}{2}})^{\frac{1}{2}}$$
5. Apply the power of a power rule $(x^m)^n = x^{m \times n}$:
$$6^{\frac{1}{2} \times \frac{1}{2}} = 6^{\frac{1}{4}}$$
### Exam Strategy & Shortcut
**Direct Transformation:** You can immediately rewrite nested square roots as a 4th root.
Since $\sqrt{\sqrt{x}} = \sqrt[4]{x} = x^{\frac{1}{4}}$, you simply multiply the inner values ($2 \times 3 = 6$) and apply the $\frac{1}{4}$ power. You can solve this mentally in 2 seconds.
### Common Pitfall
A very common mistake is adding the fractional exponents instead of multiplying them when dealing with nested roots, leading students to incorrectly choose $6^1$ or $6^{\frac{1}{2}}$. Always multiply powers when a power is raised to another power.
### Final Answer
**Therefore, the correct answer is $6^{\frac{1}{4}}$.**