Ta có\(1-\frac{1}{2}+\frac{1}{3}-\frac{1}{4}+...+\frac{1}{49}-\frac{1}{50}=1+\frac{1}{2}+...+\frac{1}{50}-2\left(\frac{1}{2}+\frac{1}{4}+...+\frac{1}{50}\right)\)
\(=1+\frac{1}{2}+...+\frac{1}{50}-\left(1+\frac{1}{2}+...+\frac{1}{25}\right)=\frac{1}{26}+\frac{1}{27}+...+\frac{1}{50}\)
\(\Rightarrowđpcm\)
C/m : 1/26+1/27+1/28+...+1/50=1-1/2+1/3-1/4+...+1/49-1/50
1/1*2+1/3*4+1/5*6+...+1/49*50=1/26+1/27+1/28+...+1/50
Chứng Minh Rằng :1/26+1/27+1/28+...+1/50=1-1/2+1/3-1/4+...+1/49-1/50
Chứng minh rằng: 1/26+1/27+1/28+...+1/50=1-1/2+1/3+1/4+...+1/49-1/50
( 1/1*2 + 1/3*4 + 1/5*6 +........+ 1/49*50 ) : ( 1/26 + 1/27 + 1/28 +.......+ 1/50 )
chứng tỏ
1/26 + 1/27 + 1/28 + ... + 1/50 =1 - 1/2 + 1/3 - 1/4 + .... + 1/49 - 1/50
Chứng minh rằng : 1/26+1/27+1/28+.......+1/50=1-1/2+1/3-1/4+.....+1/49-
1/50
Chứng minh rằng:
1/26+1/27+1/28+...+1/50=1-1/2+1/3-1/4+...+1/49-1/50
Chứng minh rằng :
\(\frac{1}{26}+\frac{1}{27}+\frac{1}{28}+....+\frac{1}{49}+\frac{1}{50}=1-\frac{1}{2}+\frac{1}{3}-\frac{1}{4}+....+\frac{1}{49}-\frac{1}{50}\)
