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## #1 2013-12-07 16:45:10

MathsIsFun
Registered: 2005-01-21
Posts: 7,660

### Finding Maxima and Minima using Derivatives

Please let me know what you think, anything I may have got wrong, suggestions, etc,

"The physicists defer only to mathematicians, and the mathematicians defer only to God ..."  - Leon M. Lederman

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## #2 2013-12-07 20:58:02

bob bundy
Registered: 2010-06-20
Posts: 8,084

### Re: Finding Maxima and Minima using Derivatives

hi MathsIsFun,

Good page, thanks.

When I was at school, my teacher wrongly called a saddle point,  a 'point of inflexion' and I think this confusion is widespread.  Would you be able to add a footnote about inflexion (or inflection if you prefer) to clarify ?

http://en.wikipedia.org/wiki/Point_of_inflexion

Bob

Children are not defined by school ...........The Fonz
You cannot teach a man anything;  you can only help him find it within himself..........Galileo Galilei

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## #3 2013-12-07 21:13:08

bobbym
bumpkin
From: Bumpkinland
Registered: 2009-04-12
Posts: 109,606

### Re: Finding Maxima and Minima using Derivatives

Hi MIF;

Good page. Please expand on the inflection points if you have the time.

In mathematics, you don't understand things. You just get used to them.
If it ain't broke, fix it until it is.
Always satisfy the Prime Directive of getting the right answer above all else.

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## #4 2013-12-07 23:06:43

anonimnystefy
Real Member
From: Harlan's World
Registered: 2011-05-23
Posts: 16,037

### Re: Finding Maxima and Minima using Derivatives

Hi MIF

Nice page.

You can maybe add that the better way of finding out if an extremum is a maximum or a minimum is looking at the sign changes at the zeros of the first derivative. It works for any function continuous between the two zeros.

Here lies the reader who will never open this book. He is forever dead.
Taking a new step, uttering a new word, is what people fear most. ― Fyodor Dostoyevsky, Crime and Punishment
The knowledge of some things as a function of age is a delta function.

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## #5 2013-12-08 15:16:29

MathsIsFun
Registered: 2005-01-21
Posts: 7,660

### Re: Finding Maxima and Minima using Derivatives

Thanks Guys! Good suggestions all.

"The physicists defer only to mathematicians, and the mathematicians defer only to God ..."  - Leon M. Lederman

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## #6 2013-12-10 11:59:18

Brainwave
Member
Registered: 2013-12-10
Posts: 2

### Re: Finding Maxima and Minima using Derivatives

Bobbym I love your words " if you cannot overcome with talent, overcome with efforts."

"MATHEMATICS", the birth place of great THINKERS.

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## #7 2013-12-19 12:06:21

MathsIsFun
Registered: 2005-01-21
Posts: 7,660

### Re: Finding Maxima and Minima using Derivatives

Wrote a page on Inflection Points ... created new topic for you guys to comment on: http://www.mathisfunforum.com/viewtopic.php?id=20306

"The physicists defer only to mathematicians, and the mathematicians defer only to God ..."  - Leon M. Lederman

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