so co dang 999999998000000001 la so chinh phuong khong ? Vi sao?

tong cua n so tu nhien le dau tien co phai la mot so chinh phuong khong ?Vi sao ?

Chung minh rang neu n la mot stn lon hon 1 thi so 2^n-1 khong the la so chinh phuong

moi tong sau co la so chinh phuong khong ? vi sao 

10!+52

1)viet day tu nhien tu 1-101 tao thanh so A 

a) A co phai hop so khong

b)A co phai so chinh phuong khong

c)A co the co 35 uoc khong

2)tim so chinh phuong co 4 chu so chu so hang nghin bang chu so hang don vi va so do co the viet duoi dang (5n+4)²

      a,   so co tong cac chu so la 2004 khong la so chinh phuong 

      b,   so co tong cac chu so la 2006 khong la so chinh phuong

      c,   n = 2004⁴+2004³+2004²+23 khong la so chinh phuong

1 so chinh phuong co chu so tan cung khong the la chu so nao

A.0

B.6

C.9

D.8

Cac ban co phai la so 0 phai khong?

CMR: A= 444...4888...89 la so chinh phuong

nc/s4 n-1c/s8

Tong cua n so tu nhien le dau tien co phai la mot so chinh phuong khong?Tại sao?