Cyclic to symmetric conversion

by MathPassionForever, Sep 4, 2019, 7:54 AM

A comparatively much smaller post (as of now), as I don't have much information on this as of now.

We can clearly see that the SD theorems are strong. But then, some inequalities are cyclic, sigh. So the basic objective of this post is to serve as a collection of inequalities which can make cyclic inequalities symmetric (and these results need to be strong themselves,for our inequality shouldn't become false after their use :P)
Here is the first one:
$a^2b + b^2c + c^2a + abc \leq \dfrac{4}{27}(a+b+c)^3 \ \forall a,b,c \in \mathbb{R}^+$
Proof: This inequality is obviously cyclic. So we may work with just 2 cases: $a\geq b \geq c$ and $a \leq b \leq c$
In either case, we have:
\begin{align*}
c(b-a)(b-c) &\leq 0\\
\iff b^2c - bc^2 + c^2a - abc &\leq 0\\
\iff a^2b + b^2c + c^2a + abc &\leq 2abc + a^2b  + bc^2 = b(a+c)^2\\
\iff a^2b + b^2c + c^2a + abc &\leq \dfrac{1}{2} (2b)(a+c)(a+c)\\
\overset{AM-GM}{\iff} a^2b + b^2c + c^2a + abc &\leq \dfrac{1}{2 \times 27} \left(\dfrac{2b+2a+2c}{3}\right)^3\\
&= \dfrac{4}{27}(a+b+c)^3
\end{align*}
Luckily, I have a question to post :-)
Question: For nonnegative reals $a,b,c$, prove that
$(a^2 + b^2 + c^2)^2 \geq (\sqrt{2}-1)(a+b+c)(\sqrt{2}(a^3+b^3+c^3)+a^2b + b^2c + c^2a)$

Solution

And in case someone doesn't find it that sharp, we have the famous and super strong Vasc inequality here!
\[ (a^2 + b^2 + c^2)^2 \geq 3(a^3b + b^3c + c^3a) \ \forall a,b,c \in \mathbb{R} \]I shall take leave here. Bye, see you soon!
This post has been edited 5 times. Last edited by MathPassionForever, Sep 5, 2019, 8:32 PM

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  • Cum'on post smth man

    by Commander_Anta78, Dec 12, 2021, 8:55 AM

  • :spam: :spam: :spam: :spam: :spam: :spam: :spam: :spam: :spam: :spam: :spam: :spam: :spam::spam: :spam: :spam: :spam: :spam: :spam::spam: :spam: :spam: :spam:

    by Project_Donkey_into_M4, Nov 8, 2021, 7:58 AM

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    by HoRI_DA_GRe8, Nov 8, 2021, 7:54 AM

  • ????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????、??????????????????????????????????????

    by whatagreatday7, Dec 11, 2020, 2:22 PM

  • @3 below, that's an april fools prank ig?

    by Synthetic_Potato, Apr 20, 2020, 9:03 AM

  • Kya yaar kuch bhi yaar

    by MathPassionForever, Apr 1, 2020, 6:50 PM

  • Nice blog yaar geo pro

    by Wizard_32, Apr 1, 2020, 6:02 PM

  • Lol okay, guess I will restart soon.

    by MathPassionForever, Apr 1, 2020, 12:51 PM

  • No celebratory posts? :P

    by Hexagrammum16, Mar 4, 2020, 6:02 AM

  • Nice blog, especially the Artzt Parabola post!

    by PhysicsMonster_01, Jan 5, 2020, 1:09 PM

  • Uhh, looks like I'm a bit too stuck b/w JEE+Schoolwork+Oly prep. Perhaps I'll blog a bit after Mains. Sorry for no posts for now. And The algebraic to geometric ineq, oh man that'll take a LOT of time.

    by MathPassionForever, Dec 4, 2019, 8:07 PM

  • New Post ??

    by gamerrk1004, Nov 24, 2019, 6:43 AM

  • When are you releasing the article on Algebraic to Geometric inequalities?

    by Math-wiz, Nov 5, 2019, 8:43 AM

  • HIGH LAVIL ... Not for me :omighty:

    by gamerrk1004, Oct 15, 2019, 12:40 PM

  • I found the properties actually!
    I'd like to see some more geo posts :)

    by Physicsknight, Oct 9, 2019, 7:57 PM

  • Chill, couldn't find that huge a compilation of properties anywhere :-)

    by MathPassionForever, Sep 28, 2019, 6:09 PM

  • Yayyy!!! Geo Posts!!! :thumbup: :trampoline:
    I earlier thought that we made a groundbreaking discovery of the Dumpty Parabola, but bery sad to know that it was already known, namely Artzt Parabola :( :( :noo:

    by AlastorMoody, Sep 27, 2019, 7:52 PM

  • Shocked!!!!

    by Math-wiz, Sep 10, 2019, 6:18 AM

  • HURRAAYYYY!! #MPF Hai Lavil!! Next Post geo?!! ;)

    by AlastorMoody, Sep 9, 2019, 6:03 PM

  • yeeee this is nicer

    by Hexagrammum16, Sep 5, 2019, 8:30 AM

  • Nice blog!

    by Mathotsav, Sep 4, 2019, 10:08 AM

  • Okay, maybe after yet another inequality post.

    by MathPassionForever, Sep 4, 2019, 8:03 AM

  • Get back to geo please :(

    by Hexagrammum16, Sep 4, 2019, 6:36 AM

  • Shout!!!
    Expecting some very interesting stuff here

    by Naruto.D.Luffy, Sep 3, 2019, 6:25 PM

  • $\frac{1}{\cos{C}}$ blog.. :)

    by Mr.Chagol, Aug 28, 2019, 9:44 AM

  • Let me try this shout thing too.(Nothing much to say as of now,..well, I hope to see some interesting stuff here).

    by Mathotsav, Aug 28, 2019, 7:15 AM

  • With that kind of support, you can expect nonzero blog posts soon :-)

    Also, those who know what I shall be posting, don't spoil for the others ;)

    by MathPassionForever, Aug 23, 2019, 5:07 PM

  • Even before you get to write I'm shouting

    by Hexagrammum16, Aug 23, 2019, 4:47 PM

  • No posts yet I'll give a shout :D

    by Pluto1708, Aug 23, 2019, 3:37 PM

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