chung minh rang:1/(1*2)+1/(3*4)+1/(5*6)+.....+1/(49*50)=1/26+1/27+1/28+....+1/50
Cho A=1-1/2+1/3-1/4+1/5-1/6+...+1/49-1/50.Chung minh A<5/6
cho A=1-1/2+1/3-1/4+1/5-1/6+...+1/49-1/50
chứng minh rằng 7/12<A<5/6
cho A=1 - 1/2 + 1/3 - 1/4 +1/5 - 1/6 +..............+1/49 -1/50
Chứng tỏ 7/12<A<5/6
A = 1 - 1/2 + 1/3 - 1/4 +... - 1/50
Chung minh 7/12 <A <5/6
cho A= 1-1/2+1/3-1/4+1/5-1/6+1/7-1/8+....1/49-1/50. Chứng minh A<5/6
Cho \(A=1-\frac{1}{2}+\frac{1}{3}-\frac{1}{4}+\frac{1}{5}-\frac{1}{6}+...+\frac{1}{49}-\frac{1}{50}\)\(\frac{1}{50}\)
Hãy chứng tỏ rằng \(\frac{7}{12}< A< \frac{5}{6}\)
\(cho:A=1-\frac{1}{2}+\frac{1}{3}-\frac{1}{4}+\frac{1}{5}-\frac{1}{6}+...+\frac{1}{49}-\frac{1}{50}\)
\(CMR:\frac{7}{12}< A< \frac{5}{6}\)
cho A=1-1/2+1/3-1/4+1/5-1/6+...+1/49-1/50