Question

if a=2+√3 then , find the value of a - 1/a

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Answer 1

$a= 2+\sqrt{3}\\\\find\\\\a-\frac{1}{a} \\\\(2+\sqrt{3})-\frac{1}{(2+\sqrt{3}) }\\\\(2+\sqrt{3})-\frac{1}{(2+\sqrt{3}) }*\frac{2-\sqrt{3} }{(2-\sqrt{3}) } \\\\(2+\sqrt{3}) - \frac{(2-\sqrt{3}) }{(4-3)}\\\\(2+\sqrt{3}) - (2-\sqrt{3})\\\\2+\sqrt{3}-2+\sqrt{3}\\\\2\sqrt{3}$