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

6/11

**** nhá kha duy tram

Answer 2

\(\left(\frac{1}{4}-1\right)\left(\frac{1}{9}-1\right)....\left(\frac{1}{121}-1\right)=-\frac{3}{4}.-\frac{8}{9}....-\frac{120}{121}=\frac{-1.3}{2.2}\cdot\frac{-2.4}{3.3}....-\frac{10.12}{11.11}=\frac{-1}{2}.-\frac{12}{11}=\frac{6}{11}\)