A=1/1^2+1/2^2+1/3^2+1/4^2+...+1/50^2
Chứng minh rằng:
a) 1/2^2 + 1/3^2 + 1/4^2 + ... + 1/n^2 < 1
b) 1/26 + 1/27 + 1/28 + ... + 1/50 = 1 – 1/2 + 1/3 – 1/4 + ... + 1/49 – 1/50
E=-1/3.(1+2+3)-1/4.(1+2+3+4)-...-1/50.(1+2+3+4+...+50)
Cho A=1/1^1+1/2^2+1/3^2+1/4^2+......+1/50^2. Chứng minh A<2.
Cho A = 2 1 1 + 2 2 1 + 2 3 1 + 2 4 1 +…+ 2 50 1 . chứng minh A< 2
Cho A=1/1^2+1/2^2+1/3^2+1/4^2+...+1/50^2. Chứng minh A<2
CMR: A=1+1/2^2+1/3^2+1/4^2+...+1/50^2>2
A= 1/1^2+1/2^2+1/3^2=1/4^2+...+1/50^2