Question

Cho S = \(\frac{1}{2}\)+\(\frac{1}{3}\)+\(\frac{1}{4}\).........+\(\frac{1}{48}\)+\(\frac{1}{49}\)+\(\frac{1}{50}\) và P = \(\frac{1}{49}\)+\(\frac{2}{48}\)+\(\frac{3}{47}\)+..........+\(\frac{48}{2}\)+\(\frac{49}{1}\)

Hãy tính \(\frac{S}{P}\)

Answer 1

Không chép lại đề nhé

Ta có:

P=\(\frac{50-49}{49}+\frac{50-48}{48}+...+\frac{50-2}{2}+\frac{50-1}{1}\)

P=\(\frac{50}{49}-\frac{49}{49}+\frac{50}{48}-\frac{48}{48}+...+\frac{50}{2}-\frac{2}{2}+\frac{50}{1}-\frac{1}{1}\)

P=\(\left(\frac{50}{49}+\frac{50}{48}+...+\frac{50}{2}\right)+\frac{50}{1}-\left(\frac{49}{49}+\frac{48}{48}+...+\frac{2}{2}+\frac{1}{1}\right)\)

P=\(50\cdot\left(\frac{1}{49}+\frac{1}{48}+...+\frac{1}{2}\right)+50-49\)                 (chỗ này gộp nha)

P=\(50\cdot\left(\frac{1}{2}+\frac{1}{3}+...+\frac{1}{48}+\frac{1}{49}\right)+1\)

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

P=\(50\cdot\left(\frac{1}{2}+\frac{1}{3}+\frac{1}{4}+...+\frac{1}{49}+\frac{1}{50}\right)\)

=>P=50S

=>\(\frac{S}{P}=\frac{S}{50S}=\frac{1}{50}\)

Vừa nãy mình nói nhầm, Sorry.

Answer 2

Tích nha

 

Answer 3

\(\frac{S}{P}=\frac{1}{2}\)

Answer 4

Cách làm dài lắm

Answer 5

 Trần Minh Hưng oi, giải ra lun jùm mk vs

Dài củm đc