\(\frac{5}{1.4}+\frac{5}{4.7}+\frac{5}{7.10}+...+\frac{5}{100.103}\)
\(=\frac{5}{3}\left(1-\frac{1}{4}+\frac{1}{4}-\frac{1}{7}+\frac{1}{7}-\frac{1}{10}+...+\frac{1}{100}-\frac{1}{103}\right)\)
\(=\frac{5}{3}\left(1-\frac{1}{103}\right)\)
\(=\frac{5}{3}.\frac{102}{103}=\frac{170}{103}\)
\(\frac{5}{1.4}+\frac{5}{4.7}+\frac{5}{7.10}+...+\frac{5}{100.103}=\frac{5}{3}.\left(\frac{3}{1.4}+\frac{3}{4.7}+\frac{3}{7.10}+...+\frac{3}{100.103}\right)=\frac{5}{3}.\left(\frac{1}{1}-\frac{1}{4}+\frac{1}{4}-\frac{1}{7}+\frac{1}{7}-\frac{1}{10}+...+\frac{1}{100}-\frac{1}{103}\right)=\frac{5}{3}.\left(\frac{1}{1}-\frac{1}{103}\right)=\frac{5}{3}.\frac{102}{103}=\frac{170}{103}\)
=5/3.(3/1.4+3/4.7+3/7.10+...+3/100.103)
=5/3.(1-1/4+1/4-1/7+1/7-1/10+...+1/100-1/103)
=5/3.(1-1/103)=5/3.102/103=170/103
đáp số : 170/103
=5.(3/1.4+3/4.7+3/7.10+...+3/100.103)
=5.(1/1+-1/4+1/4+-1/7+1/7+-1/10+...+1/100+-1/103)
=5.(1+0+0+0+...+-1/103)
=5.(1+-1/103)
=5.102/103
=510/103
Đây là câu trả lời đúng đấy.Nhớ k cho mk nha,nếu có sai thì mong bn chỉnh sửa lại giùm mk nha.
