MathYouLike MathYouLike
  • Toggle menubar
  • Toggle fullscreen
  • Toggle Search
  •    Sign up
  • QUESTIONS
  • TAGS
  • USERS
  • BADGES
  • UNANSWERD
  • ASK A QUESTION
  • BLOG
...

Futeruno Kanzuki

27/07/2017 at 16:50
Answers
1
Follow

Give 2017 positive real numbers a1 , a2 , a3 , a4 , ............... a2017 so that \(\dfrac{1}{a_1}+\dfrac{1}{a_2}+.....+\dfrac{1}{a_{2017}}=1009\)

Prove that there are at least 2 in 2017 natural numbers on equal .




    List of answers
  • ...
    Kayasari Ryuunosuke Coordinator 27/07/2017 at 17:00

    Edit post : Give 2017 positive integer numbers a1 , a2 , a3 , a4 , ............... a2017 so that 

    --------------------------------------------------------------------------------------------------------------

    Suppose a1 , a2 , a3 , a4 , ...... , a2017 are different .

    And 0 < a1 < a2 < .............. < a2017

    Since is a positive integer so that we have :

    \(\dfrac{1}{a_1}+\dfrac{1}{a_2}+........+\dfrac{1}{a_{2017}}\le\dfrac{1}{1}+\dfrac{1}{2}+.........+\dfrac{1}{2017}< \dfrac{1}{1}+\dfrac{1}{2}+\dfrac{1}{2}...............+\dfrac{1}{2}=1+\dfrac{2016}{2}=1+1008=1009\)

    From this , if those numbers are different so that the sum always smaller than 1009 , but those are equal to 1009 , that means there are 2 in 2017 numbers are equal.

    Selected by MathYouLike

Post your answer

Please help Futeruno Kanzuki to solve this problem!



Weekly ranking


© HCEM 10.1.29.225
Crafted with by HCEM