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#1 2008-12-13 20:48:26

ganesh
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Registered: 2005-06-28
Posts: 12,970

Complex Numbers - Pre University level I

1. What are the Real and Imaginary parts of the number 4 -i√3.

2. What is the conjugate of

?

3. If z=2 - i√3, then what is the value of

?

4. Express the following complex number in the forma + ib.

5. Find the real and imaginary parts of

.

6. If

,
find the conjugate of
.


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#2 2008-12-19 14:49:47

glenn101
Member
Registered: 2008-04-02
Posts: 108

Re: Complex Numbers - Pre University level I

1.
real part is 4
complex part is -i√3.
2.
the conjugate is
1/2+1/2*i
4.
5+5i   3+4i
------*------
3-4i    3+4i
= 15+20i+15i+20i^2
    --------
    25
= 15-20+20i+15i
   -------
   25
= -5+35i
   ------
    25
= -1   7
   ---+---*i
    5    5

Thats all I can do with my complex knowledge:)


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#3 2008-12-19 22:45:57

ganesh
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Registered: 2005-06-28
Posts: 12,970

Re: Complex Numbers - Pre University level I

glenn101,
Your answers are all correct,
the only trivial mistake I noticed is in answer to 1, where when the real and imaginary parts are said, the imaginary part shouldn't include 'i'.
Well done!!! smile


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#4 2008-12-28 16:07:30

careless25
Real Member
Registered: 2008-07-24
Posts: 551

Re: Complex Numbers - Pre University level I

4. (-5 + 35i)/ 25

-0.2 + 1.4i

Edit: Oops!

Last edited by careless25 (2008-12-30 04:23:35)

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#5 2008-12-28 16:55:08

ganesh
Moderator
Registered: 2005-06-28
Posts: 12,970

Re: Complex Numbers - Pre University level I

A minor mistake, careless25. Please try and post the correct answer.


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