Question 21

$$\frac{2}{2+\sqrt{2}}$$ = ?

Solution

(a+b)(a-b) = $$ a ^ {2} - b^2$$

Likewise $$ (\sqrt {2} +1)(\sqrt {2} - 1) = 2 -1 = 1$$

ie. $$ \sqrt{2} -1 = \frac {1}{\sqrt{2}+1}$$

So, the option is C

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