Maximum and minimum value Watch

Civ-217
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#1
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If  -20 \le x \le 87 and  -54 \le y \le 49 , find
a) the greatest possible value of  \frac{x}{y} .
b) the smallest possible valus of \frac{x}{y}.

a) Can the answer be "undefined number"? The book wrote the value is  \frac{87}{0} = undefined number.
b) Can the answer be "undefined number"? The book wrote the value is  \frac{-20}{0} = undefined number.

So I'm confused. Thanks.
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thomaskurian89
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#2
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Yes.
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Civ-217
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#3
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(Original post by thomaskurian89)
Yes.
Thanks but why? I don't understand why it can be a undefined number.
If you say the value is +infinity or -infinity respectively...then it's more acceptable to me.
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aqfrenzy
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How can anything over zero be given as an answer to that question? Surely it needs to be a real number for starters?
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DFranklin
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Sounds like an awful book, to be honest.
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TeamBlueGravy
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#6
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(Original post by Civ-217)
If  -20 \le x \le 87 and  -54 \le y \le 49 , find
a) the greatest possible value of  \frac{x}{y} .
b) the smallest possible valus of \frac{x}{y}.

a) Can the answer be "undefined number"? The book wrote the value is  \frac{87}{0} = undefined number.
b) Can the answer be "undefined number"? The book wrote the value is  \frac{-20}{0} = undefined number.

So I'm confused. Thanks.
Anything number, divided by 0 gives you an undefined answer. And zero is a possibility as y can equal 0.
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thomaskurian89
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(Original post by Civ-217)
Thanks but why? I don't understand why it can be a undefined number.
If you say the value is +infinity or -infinity respectively...then it's more acceptable to me.
The greatest value is +infinity and the smallest value is -infinity.
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Civ-217
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#8
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(Original post by thomaskurian89)
The greatest value is +infinity and the smallest value is -infinity.
Which means? Sorry I'm slow. :o:
For a number near to 0 from right, the value is +infinity for part a. But is this 'number' acceptable?

(Original post by DFranklin)
Sounds like an awful book, to be honest.
What should be the answer? I hope to correct the answer.

(Original post by kam_007)
Anything number, divided by 0 gives you an undefined answer. And zero is a possibility as y can equal 0.
Yes but why is the answer an undefined number?
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DFranklin
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"Undefined" or "unbounded" looks about the best answer you can give. It's the \frac{\text{blah}}{0} stuff that's truly horrible. Plus of course it's not a well posed question, given you can't give a proper answer to it (i.e. there is no "greatest value of x/y", so the question shouldn't be asking for it).
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Civ-217
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#10
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(Original post by DFranklin)
"Undefined" or "unbounded" looks about the best answer you can give. It's the \frac{\text{blah}}{0} stuff that's truly horrible. Plus of course it's not a well posed question, given you can't give a proper answer to it (i.e. there is no "greatest value of x/y", so the question shouldn't be asking for it).
Thanks.
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Kolya
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#11
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(Original post by thomaskurian89)
The greatest value is +infinity and the smallest value is -infinity.
Infinity isn't a real number! :no:
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thomaskurian89
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#12
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(Original post by Kolya)
Infinity isn't a real number! :no:
In other words, the value of x/y can be made as large as we please or as small as we please.
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