 Theory and equation derivation  Least Squares method of best fit
 http://mathforum.org/library/drmath/view/72047.html
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quadratic puzzle
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Always post answers in a "Hidecode" tag, so that others have a chance to answer the question too.
Always post answers in a "Hidecode" tag, so that others have a chance to answer the question too.
12 posts • Page 1 of 1
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quadratic puzzle
"everyone" knows how to get the line of best fit. you challenge is: given a set of data, find the quadratic equation of best fit
*hint* a bit of calculus can go a long way.
I'll post my solution next week if no one gets it.
*hint* a bit of calculus can go a long way.
I'll post my solution next week if no one gets it.

phillip1882  Apprentice
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 Location: florida
Re: quadratic puzzle
In other words, for any set of (x, y) points we must find 2nd degree polynomial (a*x^2+b*x+c) that gives the smallest error?
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vongrunt  Senior Apprentice
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Re: quadratic puzzle
exactly

phillip1882  Apprentice
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 Joined: Mon Mar 14, 2011 11:05 pm
 Location: florida
Re: quadratic puzzle
vongrunt wrote:In other words, for any set of (x, y) points we must find 2nd degree polynomial (a*x^2+b*x+c) that gives the smallest error?
pass!
Ask three DBAs a question, and you’ll get four different answers.
Brent Ozar

Thirster42  Guru

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Re: quadratic puzzle
I'm very interested but don't have time and don't really remember enough calculus. I know how to integrate... but exactly how doing that is going to help with, say, 50 random points, I don't know.
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Emtucifor  Guru

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Re: quadratic puzzle
i think this one might be a little over our heads
the highest math i took was trig, and i didn't pay a whole lot of attention (senioritus)
the highest math i took was trig, and i didn't pay a whole lot of attention (senioritus)
Ask three DBAs a question, and you’ll get four different answers.
Brent Ozar

Thirster42  Guru

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 Joined: Tue Nov 11, 2008 5:49 pm
 Location: Jefferson City, Mo
Re: quadratic puzzle
I took calculus BC and got a 5 on the calculus AP exam. I love math. With a few refreshers, I'd be back in the game.
God cries a little bit every time someone builds a database.

Emtucifor  Guru

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 Location: Bellingham, WA
Re: quadratic puzzle
Emtucifor wrote:I took calculus BC and got a 5 on the calculus AP exam.
I did the same, then pursued a mathematics degree in college. But 30+ years later, I'm certain I couldn't derive the equations to do solve this now.
Good thing others have done this for me already:
Code is hidden, SHOW
And others have previously programmed this as well:
Code is hidden, SHOW
I'm curious to see if Phillip gives us similar solutions or if he has another method in mind. In the meantime, thanks for taking me back to my mathematic roots  pun intended  for an afternoon, Phillip!
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MHGlassman  Senior Apprentice
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 Joined: Tue Jun 17, 2008 7:58 pm
 Location: Englewood, CO, USA
Re: quadratic puzzle
MHGlassman wrote:Emtucifor wrote:I took calculus BC and got a 5 on the calculus AP exam.
I did the same, then pursued a mathematics degree in college. But 30+ years later, I'm certain I couldn't derive the equations to do solve this now.
I cannot do it now either. Thus the need for refresher courses! Though for me it's been 21 years.
God cries a little bit every time someone builds a database.

Emtucifor  Guru

 Posts: 2835
 Joined: Fri May 30, 2008 9:30 pm
 Location: Bellingham, WA
Re: quadratic puzzle
Thirster42 wrote:i think this one might be a little over our heads
the highest math i took was trig, and i didn't pay a whole lot of attention (senioritus)
No not over our heads just yours . I have one tucked away somewhere just need to get it out, wich isn't going to happen any time soon I'm afraid. It's also better known as curve fitting. Some sample data would be nice so people can compare their solutions eassier.
pink fuzzy slippers

chrissie1  Senior Guru

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Re: quadratic puzzle
OK. Extra milk and cookies for anyone who writes generalized algorithm (curve fitting with nth degree polynomial)
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vongrunt  Senior Apprentice
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Re: quadratic puzzle
 TinnedTuna
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 Joined: Wed Aug 22, 2012 11:19 am
12 posts • Page 1 of 1
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