referencias bibliograficas

• http://www.sectormatematica.cl/contenidos/funoper.htm
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• http://yachay.stormpages.com/04ent/e4p.htm
 
• https://www.youtube.com/watch?v=uqf6SeCpy0Y 
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• https://www.youtube.com/watch?v=jGPG6mGrGQg
• https://www.youtube.com/watch?v=c0kgx3MGejM
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  https://www.youtube.com/watch?v=yU6YSvUXStU
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   https://www.youtube.com/watch?v=93lm3ZK65Mw