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Dido525
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Find the values of a and b so that the following is true.
 one year ago
 one year ago
Dido525 Group Title
Find the values of a and b so that the following is true.
 one year ago
 one year ago

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Dido525 Group TitleBest ResponseYou've already chosen the best response.0
I am thinking about L'Hospital's rule but I am not sure how I would apply it...
 one year ago

Rezz5 Group TitleBest ResponseYou've already chosen the best response.0
well, you can separate them, then solve them
 one year ago

Dido525 Group TitleBest ResponseYou've already chosen the best response.0
Yeah.... But I have two variables then.
 one year ago

Rezz5 Group TitleBest ResponseYou've already chosen the best response.0
are you sure it tends to infinity?
 one year ago

Rezz5 Group TitleBest ResponseYou've already chosen the best response.0
why two variables?
 one year ago

Rezz5 Group TitleBest ResponseYou've already chosen the best response.0
if you differentiate the variable you get nothing from a, but b will still be present, you can get b right?
 one year ago

Dido525 Group TitleBest ResponseYou've already chosen the best response.0
\[\lim_{x \rightarrow 0} (\frac{ \sin(2x) }{ x^3 }+a+\frac{ b }{ x^2 })=0\]
 one year ago

Dido525 Group TitleBest ResponseYou've already chosen the best response.0
Yeah. I think you are right.
 one year ago

Rezz5 Group TitleBest ResponseYou've already chosen the best response.0
ahhh, so it tends to zero?
 one year ago

Dido525 Group TitleBest ResponseYou've already chosen the best response.0
Yep :P . I typed wrong.
 one year ago

Rezz5 Group TitleBest ResponseYou've already chosen the best response.0
no problem, you can separate them then do the limits, you can spot it by inspection, very easily
 one year ago

Dido525 Group TitleBest ResponseYou've already chosen the best response.0
Hmm Let me try...
 one year ago

Rezz5 Group TitleBest ResponseYou've already chosen the best response.0
have you done it?
 one year ago

Dido525 Group TitleBest ResponseYou've already chosen the best response.0
I can't solve the limit of: \[\lim_{x \rightarrow 0}\frac{ \sin(2x) }{ x^3 }\]
 one year ago

Rezz5 Group TitleBest ResponseYou've already chosen the best response.0
you can!! differentiate 3 times until the denominator is 1,
 one year ago

Rezz5 Group TitleBest ResponseYou've already chosen the best response.0
not 1, differentiate until the denominator is a constant
 one year ago

Rezz5 Group TitleBest ResponseYou've already chosen the best response.0
sin(2)=2sin(x)cos(x)
 one year ago

Dido525 Group TitleBest ResponseYou've already chosen the best response.0
I got 4/3 .
 one year ago

Dido525 Group TitleBest ResponseYou've already chosen the best response.0
The limit.
 one year ago

Rezz5 Group TitleBest ResponseYou've already chosen the best response.0
sin(2x)/x^3 as x tends to infinity?
 one year ago

Rezz5 Group TitleBest ResponseYou've already chosen the best response.0
lol!!! im losing it today...
 one year ago

Rezz5 Group TitleBest ResponseYou've already chosen the best response.0
but still, i would have thought it was zero
 one year ago

Dido525 Group TitleBest ResponseYou've already chosen the best response.0
The Limit is infinity..... :( .
 one year ago

Dido525 Group TitleBest ResponseYou've already chosen the best response.0
We can't solve anything then.
 one year ago

Rezz5 Group TitleBest ResponseYou've already chosen the best response.0
we could, i mean if one of the variables was infinity
 one year ago

Dido525 Group TitleBest ResponseYou've already chosen the best response.0
But We can't do anything with infinity.... It's not a number.
 one year ago

Rezz5 Group TitleBest ResponseYou've already chosen the best response.0
wait are you sure it should tend to 0?
 one year ago

Dido525 Group TitleBest ResponseYou've already chosen the best response.0
Well I would assume it should tend to a finite value.
 one year ago

Rezz5 Group TitleBest ResponseYou've already chosen the best response.0
i suspect the limit should tend to infinity then for it so satisfy the limit
 one year ago

Rezz5 Group TitleBest ResponseYou've already chosen the best response.0
not necessarily, it can be infinity, let assume it was infinity, then we can do the question with ease. have you done analysis by any chance?
 one year ago

Dido525 Group TitleBest ResponseYou've already chosen the best response.0
Here is the question.
 one year ago

Rezz5 Group TitleBest ResponseYou've already chosen the best response.0
okay, no problem, assume it is infinity because i think you were right the first time round, if it was infinity just plug in infinity to the differential you had computed
 one year ago

Dido525 Group TitleBest ResponseYou've already chosen the best response.0
If we did that then a would be infinity and b would not exist.
 one year ago

Rezz5 Group TitleBest ResponseYou've already chosen the best response.0
b would, it would be x^2,
 one year ago

Dido525 Group TitleBest ResponseYou've already chosen the best response.0
but since b^2 tends to infinity the whole thing would be 0.
 one year ago

Dido525 Group TitleBest ResponseYou've already chosen the best response.0
x^2 sorry not b^2.
 one year ago

Rezz5 Group TitleBest ResponseYou've already chosen the best response.0
which would be 0, at when b/x^2 as x >0
 one year ago

Dido525 Group TitleBest ResponseYou've already chosen the best response.0
Exactly. We can't work with that.
 one year ago

Rezz5 Group TitleBest ResponseYou've already chosen the best response.0
we could, if b = 0,
 one year ago

Rezz5 Group TitleBest ResponseYou've already chosen the best response.0
0/anynumber = 0
 one year ago

Dido525 Group TitleBest ResponseYou've already chosen the best response.0
But it's not. B/x^2 is zero, not b.
 one year ago

Dido525 Group TitleBest ResponseYou've already chosen the best response.0
We don't know what b is.
 one year ago

Rezz5 Group TitleBest ResponseYou've already chosen the best response.0
a could be infinity, then this would satisfy the limit
 one year ago

Dido525 Group TitleBest ResponseYou've already chosen the best response.0
But infinity infinity is not 0.
 one year ago

Dido525 Group TitleBest ResponseYou've already chosen the best response.0
No it's not. Infinity is not a number. It's a concept.
 one year ago

Rezz5 Group TitleBest ResponseYou've already chosen the best response.0
that is true, i moment, i am trying to multi task, i jst remembered the proof that it isnt,
 one year ago

Dido525 Group TitleBest ResponseYou've already chosen the best response.0
http://en.wikibooks.org/wiki/Calculus/Infinite_Limits/Infinity_is_not_a_number
 one year ago

Rezz5 Group TitleBest ResponseYou've already chosen the best response.0
okay, you need to apply l'hpitals rule over and over again, i would recon, but first you need to put all the equation under one common factor so \[=\frac{\sin(2x) + ax^{3} + bx}{x^{3}}\]
 one year ago

Rezz5 Group TitleBest ResponseYou've already chosen the best response.0
http://answers.yahoo.com/question/index?qid=20110406112720AARpKn1 here is a better and easier way of doing it the sint is taylor expansion i think, the rest is pretty self explanatory
 one year ago

Dido525 Group TitleBest ResponseYou've already chosen the best response.0
Lol. THanks :P .
 one year ago
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