\(\frac{n\left(n+1\right)}{2}=aaa\)
\(\Rightarrow\frac{n\left(n+1\right)}{2}=111a\)
\(\Rightarrow n\left(n+1\right)=37\cdot3\cdot2\cdot a\)
\(\Rightarrow n\left(n+1\right)=37\cdot6a\)
Dễ thấy \(\orbr{\begin{cases}6a=36\\6a=37\end{cases}}\)
\(\Rightarrow\orbr{\begin{cases}a=6\\a=\frac{37}{6}\end{cases}}\)
Mà a là số tự nhiên nên a=6
\(\Rightarrow n=36\)
Tim STN n va chu so a biet:1+2+3+4+...+n=aaa
Cach lam nua nha
tim so tu nhien n va chu so a biet rang: 1+2+3+......+n = aaa
tim so tu nhien n va chu so a biet rang: 1+2+3+.....+n=aaa
tim so tu nhien n va chu so a biet
1+2+3+4+...+n=aaa
a, 1+3+5+..........+[2n-1]=1225
b, 1+2+3+........+n=aaa
tim ( a;n) E N biet a khac 0 , a < 10
va aaa= 1+2+3+.............+n
cac ban nho giai gium minh nha , viet ca cach giai nua nhe , cam on nhieu
tim a biet aaa la tong cua cac so tu nhien lien tiep tu 1 den so n nao do
Tim n thuoc N de :
1+2+3+...........+n=aaa (a khac 0)
tim so tu nhien n va chu so a thoa man 1+2+3+...+n=aaa gach dau
