Question

1/1.2+1/2.3+1/3.4+.....+1/49.50

Answer 1

Đặt \(A=\frac{1}{1.2}+\frac{1}{2.3}+\frac{1}{3.4}+....+\frac{1}{49.50}\)

\(\Rightarrow A=\frac{1}{1}-\frac{1}{2}+\frac{1}{2}-\frac{1}{3}+....+\frac{1}{49}-\frac{1}{50}\)

\(\Rightarrow A=1-\frac{1}{50}=\frac{50}{50}-\frac{1}{50}=\frac{49}{50}\)

Answer 2

bai toan nay kho

Answer 3

Đinh Đức Hùng giải đúng rồi đó

Answer 4

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

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

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

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

ủng hô mình nha