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IGCSE/GCSE/O & A Level/IB/University Student Forum
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Please help me with this question of complex numbers
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Topic: Please help me with this question of complex numbers (Read 1281 times)
Priya
Newbie
Posts: 39
Reputation: 20
Please help me with this question of complex numbers
«
on:
June 27, 2009, 10:57:16 am »
I have attached the question and my answer. The modulus of u and u^2 and the argument of u is right according the mark scheme. Can you tell me what is wrong with the argument of u^2?
The answer of argument of u^2 is pi/2
I am really grateful for all the help. Thank you so much!!
«
Last Edit: June 27, 2009, 11:02:06 am by Priya
»
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astarmathsandphysics
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Posts: 11271
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Re: Please help me with this question of complex numbers
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Reply #1 on:
June 27, 2009, 01:24:20 pm »
I think they want the ar in the range 0 to 2pi.
So do 2pi+(-3pi/2)=pi/2
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Priya
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Posts: 39
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Re: Please help me with this question of complex numbers
«
Reply #2 on:
June 27, 2009, 06:23:49 pm »
Thank you for the help =)
Just to confirm... Since it is not stated here, should I assume that for such questions, I should give my
answer between 0 and 2pi.
Thanks again.
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astarmathsandphysics
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Re: Please help me with this question of complex numbers
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Reply #3 on:
June 27, 2009, 06:41:34 pm »
Yes I would. Since they did not tell you to give your answe between o and 2pi, -3/2pi should get full marks too.
«
Last Edit: June 27, 2009, 06:43:42 pm by astarmathsandphysics
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blablabla17
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Re: Please help me with this question of complex numbers
«
Reply #4 on:
July 01, 2009, 09:21:18 am »
hey i just learnt it today...this morning...
my teacher asked us to rmb this formula...
( z)^n= r^N(COS N angle + i sin N angle)...
follow this formula then u will get the answer...
and i think what astar said is not right...
sorry for saying that...just follow the formula my teacher gave
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astarmathsandphysics
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Re: Please help me with this question of complex numbers
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Reply #5 on:
July 01, 2009, 10:38:56 am »
The formula is another method. I cant post fully on this as i am abroad on a mobile phone
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Please help me with this question of complex numbers