bài khó

B

braga

Bài trên sai!!

Lời giải:

[TEX]M= \[(1 - \frac{1}{11}) . (1 - \frac{1}{12}) . (1 - \frac{1}{13}) . ...... . (1- \frac{1}{49}) . (1 - \frac{1}{50})\] - \frac{1}{5} [/TEX]

[TEX]M=\frac{10}{11}.\frac{11}{12}.\frac{12}{13}...................\frac{48}{49}.\frac{49}{50}-\frac{1}{5}[/TEX]

[TEX]M=\frac{10}{50}-\frac{1}{5}=\fbox{0}[/TEX]
 
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