= 1.(1/1-1/50)
=49/50
49/50 < 1
Vậy M < 1
VẬY M < 1
CÓ GÌ THÌ MIK ĐƯA LỜI GIẢI CHO
TÍCH MIK NHA
\(M=\frac{1}{1.2}+\frac{1}{2.3}+...+\frac{1}{49.50}\)
\(=1-\frac{1}{2}+\frac{1}{2}-\frac{1}{3}+......+\frac{1}{49}-\frac{1}{50}=1-\frac{1}{50}=\frac{49}{50}\)
\(\frac{49}{50}<1\Rightarrow M<1\)
\(\frac{1}{1.2}+\frac{1}{2.3}+...+\frac{1}{49.50}=1-\frac{1}{2}+\frac{1}{2}-\frac{1}{3}+...+\frac{1}{49}-\frac{1}{50}\)
\(=1-\frac{1}{50}\)
\(=\frac{49}{50}\)
\(\frac{49}{50}<1\)
\(M=\frac{1}{1.2}+\frac{1}{2.3}+...+\frac{1}{49.50}\)
\(M=1-\frac{1}{2}+\frac{1}{2}-\frac{1}{3}+...+\frac{1}{49}-\frac{1}{50}\)
\(M=1-\frac{1}{50}<1\)
\(\Rightarrow M<1\)