Question

Tính giá trị biểu thức:1/11+1/12+1/13+...+1/14

Answer 1

mk làm lại:

\(\frac{1}{11}+\frac{1}{12}+\frac{1}{13}+...+\frac{1}{20}\)

=\(\left(\frac{1}{11}-\frac{11}{11}\right)+\left(\frac{1}{12}-\frac{12}{12}\right)+\left(\frac{1}{13}-\frac{13}{13}\right)+...+\left(\frac{1}{20}-\frac{20}{20}\right)\)

=\(\frac{-10}{11}+\frac{-11}{12}+\frac{-12}{13}+...+\frac{-19}{20}\)

=\(\frac{-10}{20}\)

Answer 2

\(\frac{1}{11}+\frac{1}{12}+\frac{1}{13}+...+\frac{1}{14}\)

=\(\left(\frac{1}{11}-\frac{11}{11}\right)+\left(\frac{1}{12}-\frac{12}{12}\right)+\left(\frac{1}{13}-\frac{13}{13}\right)+...+\left(\frac{1}{14}-\frac{14}{14}\right)\)

=\(\frac{-10}{11}+\frac{-11}{12}+\frac{-12}{13}+...+\frac{-13}{14}\)

=\(\frac{-10}{14}\)

Answer 3

xin lỗi, bài này mình ghi lộn, bài này là 1/11+1/12+1/13+...+1/20