Question

s=\(\frac{3}{10}\text{+}\frac{3}{40}\text{+}\frac{3}{88}\text{+}...\text{+}\frac{3}{340}\)

Answer 1

S = 1/2-1/5+1/5-1/8+1/8-...-1/20

S = 1/2-1/20

S = 9/20 nha

Answer 2

\(S=\frac{3}{2.5}+\frac{3}{5.8}+...+\frac{3}{17.20}\)

\(=\frac{1}{2}-\frac{1}{5}+\frac{1}{5}-...-\frac{1}{17}+\frac{1}{17}-\frac{1}{20}\)

\(=\frac{1}{2}-\frac{1}{20}=\frac{9}{20}\)

Answer 3

co ai ra e qua  khac ko?

Answer 4

Ta có : 

\(S=\frac{3}{10}+\frac{3}{40}+\frac{3}{88}+...+\frac{3}{340}\)

\(S=\frac{3}{2.5}+\frac{3}{5.8}+\frac{3}{8.11}+...+\frac{3}{17.20}\)

\(S=\frac{1}{2}-\frac{1}{5}+\frac{1}{5}-\frac{1}{8}+\frac{1}{8}-\frac{1}{11}+...+\frac{1}{17}-\frac{1}{20}\)

\(S=\frac{1}{2}-\frac{1}{20}\)

\(S=\frac{9}{20}\)

Vậy \(S=\frac{9}{20}\)

Chúc bạn học tốt ~ 

Answer 5

minh  cam on cac ban rat nhieu. chuc cac ban hoc gioi.