MCQ
$\big(\sqrt{-2}\big)\big(\sqrt{-3}\big)$ is equal to:
- A$\sqrt{6}$
- B$-\sqrt{6}$
- C$\text{i}\sqrt{6}$
- Dnone of these.
Solution:
$\sqrt{-2}\times\sqrt{-3}$
$=\sqrt{2}\times\sqrt{3}\times\sqrt{-1}\times\sqrt{-1}$
$=\sqrt{6}\times\text{i}\times\text{i}$
$=\sqrt{6}\times\text{i}^2$
$=-\sqrt{6} \ [\because\text{i}^2=-1]$
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