Question

Tính nhanh:

\(\frac{1}{2.4}+\frac{1}{4.6}+...+\frac{1}{98.100}\)

Answer 1

\(\frac{1}{2.4}+\frac{1}{4.6}+...+\frac{1}{98.100}\)

\(=\frac{1}{2}.\left(\frac{1}{2}-\frac{1}{4}+\frac{1}{4}-\frac{1}{6}+...+\frac{1}{98}-\frac{1}{100}\right)\)

\(=\frac{1}{2}.\left(\frac{1}{2}-\frac{1}{100}\right)\)

\(=\frac{1}{2}.\frac{49}{100}\)

\(=\frac{49}{200}\)

Answer 2

Giúp mk mấy bài nhaEdowa Conan

Answer 3

\(\frac{1}{2.4}+\frac{1}{4.6}+...+\frac{1}{98.100}\)

\(=\frac{1}{2}-\frac{1}{4}+\frac{1}{4}-\frac{1}{6}+...+\frac{1}{98}-\frac{1}{100}\)

\(=\frac{1}{2}-\frac{1}{100}\)

\(=\frac{49}{100}\)

Answer 4

=(2/2.4+2/4.6+....+2/98.100).1/2

=(1/2-1/4+1/4-1/6+....+1/98-1/100).1/2

=(1/2-1/100).1/2

=49/100