Question

[Totto chan]

Tính tổng

B=1/2×3+1/2×3×4+1/3×4×5+...+1/48×49×50

Giúp mk nha mn.......

Answer 1

[Nguyễn Lưu Hà Phương]

B= 1/1.2.3+1/2.3.4+....+1/48.49.50

B= 1/1.2-1/2.3+1/2.3-1/3.4+...+1/48.49-1/49.50

B = 1/1.2-1/49.50

B= 1/2-1/2450

B= 612/1225