neu a la so gam 200 chu so 1 va B la so gom 100 chu so 2 CMR A-B la so chinh phuong
a) cho A = 1+3+5+7+...+(2n+1) Voi n thuoc N
chung to rang A la so chinh phuong
b)B=2+4+6+8+...+2n voi n thuocN
so B co phai la so chinh phuong ko
Cho A = 5+52+......+5100
a, Tinh A
b, A la so nguyen to hay hop so ?
c, A co la so chinh phuong ko
chung minh rang neu A la so gom 200 chu so 1 va 100 chu so 2 thi A-B la so chinh phuong
a) cho A = 1 + 3 + 5 + 7 +......+(2n + 1) Voi n thuoc N
chung to rang A la so chinh phuong
b) cho B = 2 +4+6 + 8 + ....+ 2n Voi n thuocN
so B co the la chinh phuong ko
CMR neu A=111...1(200 chu so 1) va B=222...2 (100 chu so 2) thi A-B la mot so chinh phuong
S=5^1+5^2+5^3+...+5^2004 cm S la so chinh phuong
cho A= 2^0 +2^1+2^2+.....+2^2017
a,A co la so chinh phuong ko
b,A+1 co la so chinh phuong ko
Cho A = 5+52+53+...+5100
a)so A la so nguyen to hay hop so
b)so A co phai la so chinh phuong khong?