Question

Calculati aplicind formulele (a+b)^2=a^2+2ab+b^2 (a-b)^2= a^2-2ab+b^2
radical(7+4radical din 3 ) + radical(7-4 radical din 3)
.

Answer 1

$\sqrt{7+4 \sqrt{3} } = \sqrt{4+4 \sqrt{3}+ \sqrt{3^2} } = \sqrt{(2+ \sqrt{3})^2 } =2+ \sqrt{3}$
$\sqrt{7-4 \sqrt{3} } = 2- \sqrt{3} (dupa formula (a-b)^2 )$
$2+ \sqrt{2} +2- \sqrt{3} = 4$