The value of \(\frac{1}{\sqrt {7 - 4\sqrt {3}}}\) approximately is:
Answer & explanation
Correct answer: option 2
\(\frac{1}{\sqrt {7 - 4\sqrt {3}}}\) → This is always a square of any term.
\(\frac{1}{\sqrt {(2 - \sqrt {3})^2}}\) = \(\frac{1}{2 - \sqrt {3}}\) × \(\frac{2 + \sqrt {3}}{2 + \sqrt {3}}\) (rationalisation)
\(\frac{2 + \sqrt {3}}{(2)^2 - (\sqrt {3})^2}\) = \(\frac{2 + 1.7}{1}\) = 3.7