Пж помогите решить!!!!!!!!!!! 1/1*3+1/3*5+1/5*7+1/7*9+1/9*11
= 1/3 + 1/15 + 1/35 + 1/63 + 1/99 = (1155+231+99+55+35)/3465 = 1575/3465 = 5/11
Спасибо большое!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!