Question

\(\frac{1}{1.2}+\frac{1}{2.3}+\frac{1}{3.4}+\frac{1}{4.5}+.....+\frac{1}{49.50}\)

Giai cu the cho like

Answer 1

ta có : 1/1.2+1/2.3+1/3.4+1/4.5+....+1/49.50

= 1/1-1/2+1/2-1/3+1/3-1/4+1/4-1/5+.....+1/49-1/50

=1/1-1/50

= 49/50

Answer 2

\(\frac{1}{1.2}+\frac{1}{2.3}+\frac{1}{3.4}+\frac{1}{4.5}+...+\frac{1}{49.50}\)

\(=\frac{1}{1}-\frac{1}{2}+\frac{1}{2}-\frac{1}{3}+\frac{1}{3}-\frac{1}{4}+\frac{1}{4}-\frac{1}{5}+...+\frac{1}{49}-\frac{1}{50}\)

\(=\frac{1}{1}-\frac{1}{50}\)

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

Answer 3

ta có : 1/1.2+1/2.3+1/3.4+1/4.5+....+1/49.50

= 1/1-1/2+1/2-1/3+1/3-1/4+1/4-1/5+....+1/49-1/50

=1/1-1/50

=49/50

Answer 4

\(=1-\left(\frac{1}{2}+\frac{1}{2}-\frac{1}{3}+\frac{1}{3}-...-\frac{1}{49}+\frac{1}{49}-\frac{1}{50}\right)\)

\(=1-\frac{1}{50}\)

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

Answer 5

1/1.2+1/2.3+1/3.4+1/4.5+.......+1/49.50=1-1/2+1/2-1/3+1/3-1/4+1/4-1/5+.........+1/49-1/50=1-1/50=50/50-1/50=49/50

Answer 6

ta có : 1/1.2+1/2.3+1/3.4+1/4.5+....+1/49.50

= 1/1-1/2+1/2-1/3+1/3-1/4+1/4-1/5+.....+1/49-1/50

=1/1-1/50

= 49/50

Answer 7

ta có : 1/1.2+1/2.3+1/3.4+1/4.5+....+1/49.50

= 1/1-1/2+1/2-1/3+1/3-1/4+1/4-1/5+.....+1/49-1/50

=1/1-1/50

= 49/50

Answer 8

ta có : 1/1.2+1/2.3+1/3.4+1/4.5+....+1/49.50

= 1/1-1/2+1/2-1/3+1/3-1/4+1/4-1/5+.....+1/49-1/50

=1/1-1/50

= 49/50

Answer 9

ta có : 1/1.2+1/2.3+1/3.4+1/4.5+....+1/49.50

= 1/1-1/2+1/2-1/3+1/3-1/4+1/4-1/5+.....+1/49-1/50

=1/1-1/50

= 49/50