Question

1/10+1/15+1/21+...+1/120 giúp mk câu này

Answer 1

\(\frac{1}{10}+\frac{1}{15}+\frac{1}{21}+...+\frac{1}{120}\)

\(=2.\left(\frac{1}{20}+\frac{1}{30}+\frac{1}{42}+...+\frac{1}{240}\right)\)

\(=2.\left(\frac{1}{4.5}+\frac{1}{5.6}+\frac{1}{6.7}+...+\frac{1}{15.16}\right)\)

\(=2.\left(\frac{1}{4}-\frac{1}{5}+\frac{1}{5}-\frac{1}{6}+\frac{1}{6}-\frac{1}{7}+...+\frac{1}{15}-\frac{1}{16}\right)\)

\(=2.\left(\frac{1}{4}-\frac{1}{16}\right)\)

\(=2.\left(\frac{4}{16}-\frac{1}{16}\right)\)

\(=2.\frac{3}{16}=\frac{3}{8}\)

Answer 2

SẮP CÓ NGƯỜI TRẢ LỜI ĐÓ TÍC CHO NGƯỜI ĐÓ NHA

Answer 3

KB NHA