Question

Срочно помогите пожалуйста!!!

Answer 1

Ответ:

$\frac{1}{1*2*3} +\frac{1}{2*3*4} +\frac{1}{3*4*5} +\frac{1}{4*5*6} +\frac{1}{5*6*7} +\frac{1}{6*7*8} +\frac{1}{7*8*9} +\frac{1}{8*9*10} +\frac{1}{9*10*11} +\frac{1}{10*11*12} =\frac{1}{6} +\frac{1}{24}+ \frac{1}{60}+ \frac{1}{120}+ \frac{1}{210}+ \frac{1}{336} +\frac{1}{504}+ \frac{1}{720}+ \frac{1}{990} +\frac{1}{1320} =\frac{9240}{55440} +\frac{2310}{55440} +\frac{924}{55440}+ \frac{462}{55440} +\frac{264}{55440} +\frac{165}{55440} +\frac{110}{55440}+ \frac{77}{55440} +\frac{56}{55440} +\frac{42}{55440}$

$=\frac{13650}{55440} =\frac{65}{264}$

Ответ:65/264, числитель равен 65.

Пошаговое объяснение: