Question

[$\frac{1}{ \sqrt{1}+ \sqrt{2} }$ + ...... +$\frac{1}{ \sqrt{98 + \sqrt{99} } }$ = ?
Va roog , ajutoor !!

Answer 1

Rationalizam fiecare raport si obtinem:
$\sqrt{2} - \sqrt{1} + \sqrt{3} - \sqrt{2} +...+ \sqrt{99}- \sqrt{98} =\sqrt{99}-1=3 \sqrt{11} -1$