Question

Làm câu b thôi nha

Answer 1

b: =1/3-1/3+3/5-3/5+5/7-5/7+7/9-7/9+9/11-9/11-11/13+11/13+13/15

=13/15

Answer 2

`1/3 - 3/5 + 5/7 - 7/9 + 9/11 -11/13 + 13/15 +11/13 - 9/11 + 7/9 - 5/7+3/5-1/3`

`= (1/3-1/3) +(-3/5 + 3/5) +(5/7-5/7)+(-7/9+7/9)+(9/11-9/11)+(-11/13+11/13)+13/15`

`=0 + 0 +0+0+0+0+13/15`

`=13/15`

Answer 3

b]

= [ 1/3 - 1/3 ] + [ 3/5 - 3/5 ] + [ 5/7 - 5/7 ] + [ 7/9 - 7/9 ] + [ 9/11 - 9/11 ] + [ 11/13- 11/13 ] + 13/15

= 0 + 0 + 0 + 0 + 0 + 0 + 13/15

= 13/15