$(\frac{1}{2})^{-\frac{1}{2}}$ is equal to
Aptitude
Surds and Indices
Difficulty: Easy
Choose an option
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A$\frac{1}{\sqrt{2}}$
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B$2\sqrt{2}$
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C$-\sqrt{2}$
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D$\sqrt{2}$
Answer
Correct Answer: $\sqrt{2}$
Explanation
### Concept & Formula
This question assesses the direct application of negative and fractional exponents. A negative exponent flips the base (takes the reciprocal), and a fractional exponent of $1/2$ is equivalent to a square root.
$$ (\frac{a}{b})^{-n} = (\frac{b}{a})^n $$
$$ x^{\frac{1}{2}} = \sqrt{x} $$
### Step-by-Step Solution
* **Given:**
The expression to evaluate is $(\frac{1}{2})^{-\frac{1}{2}}$.
* **Calculation:**
1. Apply the negative exponent rule. To make the exponent positive, flip the fraction inside the parentheses:
$(\frac{2}{1})^{\frac{1}{2}}$
2. Simplify the base:
$2^{\frac{1}{2}}$
3. Convert the fractional exponent into its radical form:
$\sqrt{2}$
### Exam Strategy & Shortcut
This problem should be solved purely mentally in 2 seconds. You see a negative power over a fraction; immediately flip the fraction ($1/2$ becomes $2$). You see a power of $1/2$; immediately apply a square root. The result is instantly $\sqrt{2}$. No intermediate written steps are required.
### Common Pitfall
A very frequent mistake is assuming that a negative exponent will result in a negative final answer, leading students to incorrectly choose option (c) $-\sqrt{2}$. Exponents dictate repeated multiplication or reciprocals, not the positive/negative sign of the base.
### Final Answer
**Therefore, the correct answer is $\sqrt{2}$.**