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#1 2018-06-20 15:36:35

Mathando
Member
Registered: 2018-06-20
Posts: 3

Please help explain math expansion

Could someone help explain the expansion below:
Square(x+Δx) -> square(x)+ 2x Δx + square(Δx)

In my understanding, below should be the correct expansion:
Square(x+Δx) -> square(x) + square(Δx)

My question is from reading “introduction to derivative” article on MathIsFun


Thanks,

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#2 2018-06-20 21:16:18

ganesh
Administrator
Registered: 2005-06-28
Posts: 26,286

Re: Please help explain math expansion

Hi Mathando,

Introduction to Derivative.

The slope formula is:    


Put in
and
.
Simplify
and
cancel

Simplify more (divide through by Δx):    = 2x + Δx
Then as Δx heads towards 0 we get:    = 2x


It is no good to try to stop knowledge from going forward. Ignorance is never better than knowledge - Enrico Fermi. 

Nothing is better than reading and gaining more and more knowledge - Stephen William Hawking.

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#3 2018-06-21 07:27:45

Mathando
Member
Registered: 2018-06-20
Posts: 3

Re: Please help explain math expansion

http://www.mathisfunforum.com/latex/b/1/4e18c1f224b02b22693d61ffad4eff1.gif

Could you elaborate about more. Where does 2x delta x come from ?


Thanks

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#4 2018-06-21 14:59:34

ganesh
Administrator
Registered: 2005-06-28
Posts: 26,286

Re: Please help explain math expansion

Hi,


.


It is no good to try to stop knowledge from going forward. Ignorance is never better than knowledge - Enrico Fermi. 

Nothing is better than reading and gaining more and more knowledge - Stephen William Hawking.

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#5 2018-06-21 23:53:53

Mathando
Member
Registered: 2018-06-20
Posts: 3

Re: Please help explain math expansion

Thanks

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