Question

rezolvati ecuatia : aranjamente de n luate cate 2 =30 , n mai mare sau egal cu 2

Answer 1

n!/(n-2)!=30
metoda  ne academica ("gandim")
(n-1)*n=30=5*6
n=6≥2 convine

metoda "muncim"
n²-n-30=0
n1,2= [1+-√(1+120)]/2= (1+-11)/2
n1=-5∉N
n2=6≥2 convine