Algebra för Ma1A: Skillnad mellan sidversioner

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Rad 5: Rad 5:
Wu's Squaring Trick, named after the famous Scott Wu, is a technique used to quickly square numbers over 25 in your head. It uses the identity
Wu's Squaring Trick, named after the famous Scott Wu, is a technique used to quickly square numbers over 25 in your head. It uses the identity


:                           n<sup>2</sup> = (n-25) \cdot 100 + (n-50)<sup>2</sup>
:                   <math>                   n^2 = (n-25) \cdot 100 + (n-50)^2 </math>  


For example,
For example,
Rad 11: Rad 11:
:                <math>            62^2 = 37 \cdot 100 + 12^2 = 3844    </math>   
:                <math>            62^2 = 37 \cdot 100 + 12^2 = 3844    </math>   
:
:
:                           44^2 = 19 \cdot 100 + 6^2 = 1936
:               <math>                      44^2 = 19 \cdot 100 + 6^2 = 1936 </math> 
:
:
:                           77^2 = 52 \cdot 100 + 27^2 = 5929
:                         <math>            77^2 = 52 \cdot 100 + 27^2 = 5929 </math> 


These mental computations can be done very quickly with just a little practice, so amaze your friends with how fast you can square two digit numbers!
These mental computations can be done very quickly with just a little practice, so amaze your friends with how fast you can square two digit numbers!

Versionen från 1 oktober 2014 kl. 21.21

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Från Quora:

Wu's Squaring Trick, named after the famous Scott Wu, is a technique used to quickly square numbers over 25 in your head. It uses the identity

[math]\displaystyle{ n^2 = (n-25) \cdot 100 + (n-50)^2 }[/math]

For example,

[math]\displaystyle{ 62^2 = 37 \cdot 100 + 12^2 = 3844 }[/math]
[math]\displaystyle{ 44^2 = 19 \cdot 100 + 6^2 = 1936 }[/math]
[math]\displaystyle{ 77^2 = 52 \cdot 100 + 27^2 = 5929 }[/math]

These mental computations can be done very quickly with just a little practice, so amaze your friends with how fast you can square two digit numbers!