Question

Aflati n e(apartine) N,stiind ca n-1<2√5

Answer 1

Metoda I
n-1<2√5
n<2√5+1
2√5+1≈2·236+1≈5,472
n∈{0,1,2,3,4,5}

Metoda II
n<2√5+1≤√20+1<√25+1
n<6
n∈{0,1,2,3,4,5}