Rationalise the denominator in the following expression:
$\frac{1}{\sqrt{5}-\sqrt{3}}$
$\frac{1}{\sqrt{5}-\sqrt{3}}$
(A) To rationalise the denominator,multiply the numerator and the denominator by the conjugate of the denominator,which is $(\sqrt{5} + \sqrt{3})$.
$\frac{1}{\sqrt{5}-\sqrt{3}} \times \frac{\sqrt{5}+\sqrt{3}}{\sqrt{5}+\sqrt{3}}$
$= \frac{\sqrt{5}+\sqrt{3}}{(\sqrt{5})^2 - (\sqrt{3})^2}$
$= \frac{\sqrt{5}+\sqrt{3}}{5 - 3}$
$= \frac{\sqrt{5}+\sqrt{3}}{2}$
$\frac{1}{\sqrt{5}-\sqrt{3}} \times \frac{\sqrt{5}+\sqrt{3}}{\sqrt{5}+\sqrt{3}}$
$= \frac{\sqrt{5}+\sqrt{3}}{(\sqrt{5})^2 - (\sqrt{3})^2}$
$= \frac{\sqrt{5}+\sqrt{3}}{5 - 3}$
$= \frac{\sqrt{5}+\sqrt{3}}{2}$
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