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November 01, 2025, 03:09:58 pm

Author Topic: How would -4 < Re(z) < 4 look like?  (Read 1138 times)  Share 

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ahat

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How would -4 < Re(z) < 4 look like?
« on: October 07, 2013, 09:09:37 pm »
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The answer is C, I'm wondering how the other relations would look like? :)
(I initially thought it could be b)
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lzxnl

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Re: How would -4 < Re(z) < 4 look like?
« Reply #1 on: October 07, 2013, 09:19:02 pm »
+4
A is basically a semicircle radius 16
B is still the entire circle as everywhere in the circle |z|<=4 satisfies -4<=Re(z)<=4
C is the right answer as you know
For D, z*z bar = (x+iy)(x-iy)=x^2+y^2, so D is the same as A
E is x^2+y^2<=4; the second restriction is correct, but it's a semcircle of radius 2.
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ahat

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Re: How would -4 < Re(z) < 4 look like?
« Reply #2 on: October 07, 2013, 09:24:40 pm »
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B is still the entire circle as everywhere in the circle |z|<=4 satisfies -4<=Re(z)<=4

Oh my gosh, smack my head.
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abeybaby

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Re: How would -4 < Re(z) < 4 look like?
« Reply #3 on: October 07, 2013, 10:40:17 pm »
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Can I ask, where did this question come from? It's not a vcaa paper is it?

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ahat

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Re: How would -4 < Re(z) < 4 look like?
« Reply #4 on: October 07, 2013, 11:02:32 pm »
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Kilbaha 2006
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BubbleWrapMan

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Re: How would -4 < Re(z) < 4 look like?
« Reply #5 on: October 07, 2013, 11:09:27 pm »
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I wonder if VCAA would care about the open circle at the origin which should be there if C is correct. I think they avoid questions with open circles...
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abeybaby

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Re: How would -4 < Re(z) < 4 look like?
« Reply #6 on: October 07, 2013, 11:09:55 pm »
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I wonder if VCAA would care about the open circle at the origin which should be there if C is correct. I think they avoid questions with open circles...
Exactly why I asked!

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