Question

tính nhanh

1/2+1/14+1/35+1/65+1/104+1/152

Answer 1

1/2 + 1/14 + 1/35 + 1/65 + 1/104 + 1/152  = 12/19 nhé bạn !

Answer 2

de nhu an banh

Answer 3

Đặt S = tổng trên

2S=1/4+1/28+1/70+1/130+1/208+1/304

2S=1/1.4+1/4.7+1/7.10+1/10.13+1/13.16+1/16.19

2S=1/3.(3/1.4+3/4.7+3/7.10+3/10.13+3/13.16+3/16.19)

2S=1/3.(1-1/19)

2S=1/3.18/19

2S=6/19

 S=6/19:2

 S=3/19