Question

[trần phan thế dương]

\(\frac{5}{1.3}+\frac{5}{3.5}+\frac{5}{5.7}+\)......+\(\frac{5}{49.51}\)

Answer 1

[Neo Queen Serenity]

\(\frac{5}{1.3}+\frac{5}{3.5}+\frac{5}{5.7}+...+\frac{5}{49.51}\)

\(=\frac{1}{2}.\left(\frac{1}{1}-\frac{1}{3}+\frac{1}{3}-\frac{1}{5}+...+\frac{1}{49}-\frac{1}{51}\right)\)

\(=\frac{1}{2}.\left(\frac{1}{1}-\frac{1}{51}\right)=\frac{1}{2}.\frac{50}{51}=\frac{25}{51}\)

Answer 2

[Võ Hiền Anh]

5/2×(1/1-1/3+1/3-1/5+1/5-1/7+....+1/49-1/51)

5/2×(1/1-1/51)

5/2×50/51

2 và 23/51(hỗn số)

K cho mk nha bn, ok, cảm ơn bn nhìu