Question

tinh tong 100 so hang dau tien

1/1.2;1/2.3;1/3.4;1/4.5......

 

Answer 1

ta biết

1/1.2=1/1-1/2;1/2.3=1/2-1/3............;1/n-1/n+1=1/n(n+1)

=>1/1.2+1/2.3+............+1/100.101

=1/1-1/2+1/2-1/3+1/3-1/4+..............+1/99-1/100+1/100-1/101

=1-1/101=100/101

Answer 2

ta biet

1/1.2=1/1-1/2;1/2.3=1/2-1/3............;1/n-1/n+1=1/n(n+1)

=>1/1.2+1/2.3+............+1/100.101

=1/1-1/2+1/2-1/3+1/3-1/4+..............+1/99-1/100+1/100-1/101

=1-1/101=100/101

k mk nha

Answer 3

ta biết

1/1.2=1/1-1/2;1/2.3=1/2-1/3............;1/n-1/n+1=1/n(n+1)

=>1/1.2+1/2.3+............+1/100.101

=1/1-1/2+1/2-1/3+1/3-1/4+..............+1/99-1/100+1/100-1/101

=1-1/101=100/101

Answer 4

100/101