Question

a=(√3+√5)(3-√15)+(1-√3)^2+4√3
Arătați ca a este nr natural.

Answer 1

$A = 3 \sqrt{3} -\sqrt{45} + 3 \sqrt{5} -\sqrt{75}+1-2\sqrt{3}+3+4 \sqrt{3} = 5\sqrt{3}- \sqrt{75} + 4$
$5 \sqrt{3} - 5 \sqrt{3} + 4 = 4$

4 ∈ N