\(S=1+2+2^2+...+2^{2015}\)
\(\Rightarrow2S=2+2^2+...+2^{2016}\)
\(\Rightarrow2S-S=S=2^{2016}-1\)
\(S+18=2^{2016}+18-1=2^{2016}+17\)
Tự làm , đề sai rroi
Cho A= 2. 4. 6. 8. 10 + 18
a) A co chia het cho 2, cho 3, cho 9 ko? vi sao?
b) A la hop so hay so nguyen to? vi sao?
c) Aco phai la so chinh phuong ko? vi sao?
cho S=1^2+2^2+3^2+...+56^2. S co phai la so chinh phuong khong
cho a=2+2^2+2^3+............+2^2015 Chung minh a ko chia het 7
a co la so chinh phuong ko vi sao
tim so tu nhien lon hon 0 sao cho tong
1!+2!+...+n! la so chinh phuong
b)tim 1 so co 4 chu so sao cho so do vua la s chinh phuong vua la so lap phuong
S=2+2^2+2^3+…+2^2012. S co phai 1 so chinh phuong ko
Tong sau co phai la so chinh phuong ko: 52+122
tong S =1^2+2^2+3^2+...+30^2 co phai so chinh phuong khong?
Giup mih nhe Chieu mai nop rui . Thnks truoc ^^
Cho S = 2011.72015+4.19766 mu2015
Tim chu so tan cung cua S.S co phai la so chinh phuong ko?
tong cua n so tu nhien le dau tien co phai la mot so chinh phuong khong ?Vi sao ?
