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find the limit
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bgbgbgbg
Hodge Conjecture
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#1
find the limit
find the limit

find the limit:
lim (sinx)/x as x goes to 0 if x in degrees

PostPosted: Tue Oct 27, 2009 8:52 pm  Back to top 
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tobeno_1
Poincare Conjecture
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#2
Re: find the limit
find the limit

bgbgbgbg wrote:
find the limit:
lim (sinx)/x as x goes to 0 if x in degrees

Isn't it 1?
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PostPosted: Tue Oct 27, 2009 8:59 pm  Back to top 
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bgbgbgbg
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#3
please

notice that x in degrees not in radian

PostPosted: Tue Oct 27, 2009 9:16 pm  Back to top 
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evoluciona
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#4
Re: please

bgbgbgbg wrote:
notice that x in degrees not in radian


Make the substitution u = x*2Pi/360. x tends to 0+ iff u tends to 0+. Replace all x's with u.

PostPosted: Tue Oct 27, 2009 9:22 pm  Back to top 
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phymax
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#5
it doesnt even count much in hyperreals.

PostPosted: Fri Oct 30, 2009 7:04 am  Back to top 
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mavropnevma
Yang-Mills Theory
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#6
\lim_{x \to 0} \frac {\sin x} {x} = 1. It does not matter the unit of measure for x, be it radians, degrees (or maybe \textrm{Fahrenheit}^{\circ} Smile ).
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PostPosted: Fri Oct 30, 2009 11:30 pm  Back to top 
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shyong
Navier-Stokes Equations
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#7
it would makes sense if you could tell what is the meaning of a real number divided by a degree ?
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PostPosted: Sat Oct 31, 2009 12:08 am  Back to top 
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jmerry
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#8
Given the level of understanding this question was asked at, the last few posts really don't fit.

There is a perfectly sensible \sin function defined on angles, which can be measured in degrees. Before calculus, degrees are as good as any angle measurement system, and cive us nice numbers for nice angles.
So, now we want to develop the calculus of trigonometric functions. The first crucial limit that comes up is this one: what is \lim_{x\to 0}\frac{\sin x}{x}. Since we don't know any better, that angle is marked in degrees for now. What is the value of this limit? Some ugly number; if we look closer, it turns out to be \frac{\pi}{180}.
We don't like that, so we invent an entirely new angle measurement, called the radian. Scaling the angle measurement changes the limit, and for the radian's arclength scaling it turns out to be 1.
That is the point of radians. From there on, we never use degrees in a calculus setting again.

PostPosted: Sat Oct 31, 2009 12:35 am  Back to top 
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