MTH1020 Study Guide - Final Guide: Imaginary Number, Set Notation
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Complex numbers
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WHAT IS A COMPLEX NUMBER?
Definition: A complex number is a number of the form
where and are real numbers, and .
Note: The definition of complex numbers uses the definition of real numbers. Complex numbers
are defined in terms of real numbers.
The set of complex numbers is denoted . Thus, in set notation,
We often write to denote a complex number,
We say that is the real part of and is the imaginary part of .
We write
and .
Examples
is a complex number with real part and imaginary part :
, and .
If , then is a complex number such that
and
The number is a complex number with real part and imaginary part
and
If , then is a complex number such that
and
Document Summary
Note: the definition of complex numbers uses the definition of real numbers. Complex numbers are defined in terms of real numbers. Definition: a complex number is a number of the form where and are real numbers, and 2= (cid:883). The set of complex numbers is denoted . We often write to denote a complex number, We say that is the real part of and is the imaginary part of . We write and (cid:120) (cid:153) examples (cid:120) (cid:884)+(cid:885) is a complex number with real part (cid:884) and imaginary part (cid:885): If =(cid:884)(cid:885). 7 (cid:886), then is a complex number such that. Re (cid:4666)(cid:4667)= and im (cid:4666)(cid:4667)= (cid:120) the number (cid:883). (cid:887) is a complex number with real part and imaginary part. If =(cid:883)(cid:884), then is a complex number such that. Things to note (cid:120) perhaps surprisingly, the imaginary part of a complex number is not an imaginary are often called imaginary or pure imaginary numbers.