12-240/Classnotes for Thursday September 20: Difference between revisions
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== Complex number == |
== Complex number == |
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'''Definition:''' |
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''' C'''={(a,b): a, b <math>\in\!\,</math> '''R'''} |
''' C'''={(a,b): a, b <math>\in\!\,</math> '''R'''} |
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i^2=-1 |
i^2=-1 |
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'''C''' contains '''R''' as {(a,0)} ( actually, this is not the set of real number but a copy of it ) |
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[[Image:IMG.jpg]] |
[[Image:IMG.jpg]] |
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Revision as of 12:33, 21 September 2012
In this class, the professor completes the lecture about complex number and then introduces vector space.
Complex number
C={(a,b): a, b R}
1 ( of C) = (1,0); 0 ( of C)= (0,0)
i=(0,1)
(a,b)+(c,d)=(a+c,b+d); (a,b)x(c,d)=(ac-bd,ad+bc)
i^2=-1
C contains R as {(a,0)} ( actually, this is not the set of real number but a copy of it )
