cube root of (-89)

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uptowngirl92
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Topic: cube root of (-89)
PostTue Nov 03, 2009 6:23 pm
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The value of cube root of (-89) is..?

Between -9 and 10
Between -8 and -9
Between -4 and 5
Between -3 and 4
Undefined

...................

[spoiler=]Is'nt the root of any negative number undefined?[/spoiler]
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PostTue Nov 03, 2009 8:14 pm
uptowngirl92 wrote:
The value of cube root of (-89) is..?

Between -9 and 10
Between -8 and -9
Between -4 and 5
Between -3 and 4
Undefined

...................

[spoiler=]Is'nt the root of any negative number undefined?[/spoiler]
IMHO
Sqrt of a -ve no. is imaginery,
but here its cube root
for this one i hope u have a typo in choice a) it should be -10

OA pls
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NikolayZ
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PostWed Nov 04, 2009 7:29 am
Well, still we can answer this question.

-89 is negative, hence the number^3=-89 must be negative too.
(-3)^3=-27
(-4)^3=-64
(-5)^3=-125,
Hence the cube root of (-89) must be in (-4;-5), the only segment that must include this number is A: (-9;10)
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PostWed Nov 04, 2009 10:16 am
The answer is between -4 and -5.
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heshamelaziry
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PostWed Nov 04, 2009 11:38 am
IMO -4, 5
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