Các câu hỏi tương tự
a,A=1/1^2+1/2^2+1/3^2+1/4^2+...+1/50^2.chung minh rang a<2
b;2^1+2^2+2^3+...+2^30.chung minh rang B chia het cho21
ChoA=1/1^2+1/2^2+1/3^2+1/4^2+...+1/50^2
Chung minh A <2
Cho A = 1/3^2 + 1/4^2 + 1/5^2 +...+ 1/50^2
Chung minh 1/4 < A < 4/9
A=1/2^2+1/3^2+...+1/50^2 , chung minh A<1
cho A=\(\frac{1}{1^2}+\frac{1}{2^2}+\frac{1}{3^2}+\frac{1}{4^2}+.....+\frac{1}{50^2}\)
Chung minh rang A<2
Chung minh
A=1/2+1/2^2+15/2^3+....+1/2^50<1
Cho A=1/3^2+1/4^2+1/5^2+...+1/50^2
Chung to rang a,A>1=4 b,A>4/9
Cho A=1/3^2+1/4^2+1/5^2+...+1/50^2
Chung to rang a,A>1=4 b,A>4/9
CHO A=\(\frac{1}{1^2}+\frac{1}{2^2}+\frac{1}{3^2}+....+\frac{1}{50^2}\)
CHUNG MINH RANG A<2