Question

TÍNH :

 1-\(\frac{1}{3.5}\)\(-\frac{1}{5.7}-\frac{1}{7.9}-...-\frac{1}{53.55}-\frac{1}{55.57}\) 

GIÚP MIK NHOA AHIHI   ^ \/ ^

Answer 1

=1-(1/3.5+1/3.7+1//7.9+...+1/55.57)

=1-1/2.(2/3.5+2/5.7+2/7.9+...+2/55.57)

=1-1/2(1/3-1/5+1/5-1/7+1/7-1/9+...+1/55-1/57)

=1-1/2(1/3-1/57)

=1-1/2.18/57

=1-9/57

=48/57

Answer 2

=

1-(1/3.5+1/5.7+1/7.9+....+1/53.55+1/55.57)

=1-1/2.[1/3-1/5+1/5-1/7+1/7-1/9+...+1/53-1/55+1/55-1/57]

=1-1/2.[1/3-1/57]

=1-1/2.54/171

=1-28/171

=143/171.

Answer 3

Ta có: 1 - 1/3.5 - 1/5.7 - 1/7.9 - ...... - 1/53.55 - 1/55.57

=> 1 - ( 1/3.5 + 1/5.7 + 1/7.9 + ......... + 1/53.55 + 1/55.57 )

=>  1 - ( 1/3 - 1/5 + 1/5 - 1/7 + 1/7 - 1/9 + ....... + 1/53 - 1/55 + 1/55 - 1/57 )

=> 1 - ( 1/3 - 1/57 )

=> 1 - 6/19

=> 13/19