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Problem Of The Week 30

with 6 comments


Let b be an odd square and n be any natural number. Then b=n^3+2n^2. Find b?

Written by Implex

September 27, 2008 at 10:31 am

6 Responses

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  1. If we have to find only 1 value
    441=7^3+ 2(7)^2 satisfies the condition.

    tyro

    September 27, 2008 at 12:13 pm

  2. Find the smallest b ..
    The question is incomplete. sorry!

    outtimed

    September 27, 2008 at 12:48 pm

  3. The smallest value of b will then be 3 as the question does not say perfect square.
    3= (1)^3 + 2 (1)^2

    tyro

    September 27, 2008 at 1:41 pm

  4. what does odd square mean, if it is not perfect square????

    outtimed

    September 27, 2008 at 1:48 pm

  5. b= n^3 +2 n^2
    = n^2(n+2)
    such that b makes for a perfect square. both n^2 and n+2 have to be odd.
    so n can be an odd natural number such that b is a perfect square.
    so the smallest b is 441 only.
    But I still think it should be mentioned as perfect square.

    tyro

    September 27, 2008 at 2:14 pm

  6. yaar odd square means perfect square,
    there is nothing called an imperfect square!

    outtimed

    September 27, 2008 at 2:55 pm


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