2/1*3+2/3*5+2/5*7+...+2/99*101

Question

2/1*3+2/3*5+2/5*7+...+2/99*101

Answer 1

Нужно 2 и 1*3+2/3*5+2/5*7+...+2/99*101 поменять местами 
1/1-1/3+1/3-1/5+1/5....=1-1/101