Question

tính hợp lý

2/3+3/5+2/7+2/9

..............................

11/3+11/5+11/7+11/9

................... là dấu phân số

 

(1/4-1).(1/9-1).(1/16-1).(1/25-1)......(1/121-1)

giúp mình nha

 

Answer 1

\(\frac{\frac{2}{3}+\frac{2}{5}+\frac{2}{7}+\frac{2}{9}}{\frac{11}{3}+\frac{11}{5}+\frac{11}{7}+\frac{11}{9}}=\frac{2\left(\frac{1}{3}+\frac{1}{5}+\frac{1}{7}+\frac{1}{9}\right)}{11\left(\frac{1}{3}+\frac{1}{5}+\frac{1}{7}+\frac{1}{9}\right)}=\frac{2}{11}\)