Wikipedia:Reference desk/Archives/Mathematics/2015 April 6

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April 6

quadratic equations

What practical use do quadratic equations have in normal everyday life? Why did they make us learn them in school? — Preceding unsigned comment added by Partypopperstopper (talk • contribs) 00:49, 6 April 2015 (UTC)

Our own article has the section Quadratic equation#Examples and applications. Additionally, you may wish to read Real World Examples of Quadratic Equations, 101 uses of a quadratic equation (with Part II here), and Everyday Examples of Situations to Apply Quadratic Equations. -- ToE 02:25, 6 April 2015 (UTC)

Yeah, but what about the second question? YohanN7 (talk) 12:16, 6 April 2015 (UTC)

They didn't make you learn quadratic equations in school. They tried but failed. Bo Jacoby (talk) 12:49, 6 April 2015 (UTC).

*Grin* Mathematics education#Objectives touches on the subject. -- ToE 15:25, 6 April 2015 (UTC)

As to why do we learn them in school. I think a lot is to do with that its one of the few things which is easily solvable. The number types of equations which can be easily solved with limited technical skills is pretty limited. We can solve linear equations, quadratics and thats about it. Cubics and quartics can be solved but its ugly and beyond what we would expect high school to be able to do. This lack of solvable problems mean that there is perhaps too much emphasis on quadratics.--Salix alba (talk): 22:32, 8 April 2015 (UTC)

Agreed. I see less and less need to memorize formulas in the future, as any smart phone should be able to do the math for you, if you really need it. Instead, we should emphasize applications of math more than the mechanics. For example, many people don't seem to know how to do math involving percentages, interest, etc., which does come up often in everyday life. StuRat (talk) 22:43, 8 April 2015 (UTC)

Counterexample to the Navier–Stokes existence and smoothness problem

Is it regarded as even remotely plausible by mathematicians that their may be a case for which the Navier–Stokes equations have no smooth and globally defined solution? The Millennium Prize formulation is "prove or give a counterexample", but I see discussion of a possible proof but none of a counterexample. Is it unrealistic? JaneStillman (talk) 15:31, 6 April 2015 (UTC)

Yes. Navier–Stokes_existence_and_smoothness#Partial_results point 5 indicates the possibility that a solution may blow up in a finite time. Bo Jacoby (talk) 19:24, 6 April 2015 (UTC).