\(\frac{1}{1.2}+\frac{1}{2.3}+\frac{1}{3.4}+...+\frac{1}{200.201}\)
\(=1-\frac{1}{2}+\frac{1}{2}-\frac{1}{3}+...+\frac{1}{200}-\frac{1}{201}\)
\(=1-\frac{1}{201}\)
\(=\frac{200}{201}\)
\(\frac{1}{1.2}+\frac{1}{2.3}+\frac{1}{3.4}+...+\frac{1}{200.201}\)
\(=\frac{1}{1}-\frac{1}{2}+\frac{1}{2}-\frac{1}{3}+\frac{1}{3}-\frac{1}{4}+...+\frac{1}{200}-\frac{1}{201}\)
\(=1-\frac{1}{201}=\frac{200}{201}\)
Ủng hộ nha,tớ ko ăn cóp đâu.
\(\frac{1}{1.2}+\frac{1}{2.3}+\frac{1}{3.4}+\frac{1}{200.201}\)
\(=\frac{1}{1}-\frac{1}{2}+\frac{1}{2}-\frac{1}{3}+\frac{1}{3}-\frac{1}{4}+...+\frac{1}{200}-\frac{1}{201}\)
\(=\frac{1}{1}-\frac{1}{201}\)
\(=\frac{200}{201}\)
\(\frac{1}{1.2}+\frac{1}{2.3}+\frac{1}{3.4}+.....+\frac{1}{200.201}\)
\(=1-\frac{1}{2}+\frac{1}{2}-\frac{1}{3}+\frac{1}{3}-\frac{1}{4}+...+\frac{1}{200}-\frac{1}{201}\)
\(=1-\frac{1}{201}\)
\(=\frac{200}{201}\)