Question

tính cách tổng sau bằng  cách hợp lý nhất.A=1/1×2+1/2×3+1/3×4+...+1/49×50

Answer 1

A = 2-1/1x2 + 3-2/2x3 + ..... + 50-49/49x50

   = 1 - 1/2 + 1/2 - 1/3 + ........ + 1/49 - 1/50

   = 1 - 1/50

   = 49/50

Tk mk nha

Answer 2

mình không chep lại đề bài đâu

A=1/1-1/2+1/2-1/3+1/3-1/4+.....+1/49-1/50

A=1/1-0-0-0-....-0-1/50

A=1/1-1/50

A=49/50

Answer 3

A=1/1*2+1/2*3+...+1/49*50

A=2-1/1*2+3-2/2*3+...+50-49/49*50

A=2/1*2-1/1*2+3/2*3-2/2*3+...+50/49*50-49/49*50

A=1-1/2+1/2-1/3+...+1/49-1/50

A=1-1/50

A=49/50

Answer 4

=\(\frac{49}{50}\)