Yahoo Answers is shutting down on May 4th, 2021 (Eastern Time) and beginning April 20th, 2021 (Eastern Time) the Yahoo Answers website will be in read-only mode. There will be no changes to other Yahoo properties or services, or your Yahoo account. You can find more information about the Yahoo Answers shutdown and how to download your data on this help page.

Faz
Lv 7
Faz asked in Science & MathematicsMathematics · 1 decade ago

Prove the Inequality?

(7!)^(1/7) < (8!)^(1/8)

Here's what I did. First raise to the power 56 on both sides to get:

7!^8 < 8!^7

7!^7 < ( 8!^7) / 7!

7!^7 < ( 8!^6) X 8

630(7!^6) < ( 8!^6)

How can I show it more explicitly??

Update:

630(7!^6) < ( 8!^6)

Maybe like this?

630 < 8^6

4 Answers

Relevance
  • Rich
    Lv 7
    1 decade ago
    Favorite Answer

    the 7th root of 7! is 3.380015159.....

    the 8th root of 8! is 3.7643505.....

    so it is true

    good luck

  • 1 decade ago

    Go from 7!^8 < 8!^7

    8!^7=7!^7*8^7

    7!^8 < 7!^7*8^7

    7! < 8^7

    From here you could calculate 7! and 8^7. Or you could say that each of these terms is the product of 7 positive integers. Since 8^7 is the product of 7 eights and 7! is the product of 7 integers that are all less than 8, 8^7 is greater than 7!.

    8>7>6>5>4>3>2>1

    So 8>7

    8*8>7*6

    8*8*8>7*6*5

    and so on.

  • 1 decade ago

    7!^8 < 8!^7

    (7!^7)7! < 8!^7

    7! < (8!^7)/(7!^7)

    7! < 8^7

    which is true bc 7! < 7^7 < 8^7

    of course you would start with the bottom statement and work backwards

  • ted s
    Lv 7
    1 decade ago

    after your 1st step try dividing both sides by [7!]^7....then it is a simple argument to make

Still have questions? Get your answers by asking now.