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OpenStudy (zzr0ck3r):
can you use LHopital's?
OpenStudy (cggurumanjunath):
type the equation properly.
OpenStudy (anonymous):
lim x=0 (xsinx)/(2+2cosx)
OpenStudy (dls):
2+2cosx? are u kidding me?
OpenStudy (dls):
u wrote 2-2cosx in the question
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OpenStudy (anonymous):
o i mean 2-2cosx sorry
OpenStudy (dls):
\[\Huge \frac{x sinx}{2(1+cosx)}=\frac{2xsin \frac{x}{2}\cos{\frac{x}{2}}}{2(2\cos^2 \frac{x}{2})}\]
\[\Huge \frac{\cancel{2}x \{\sin \frac{x}{2}\cancel{cos{\frac{x}{2}}}}{\cancel{2}(2\cancel{\cos^2 \frac{x}{2}})}\]
\[\Huge \frac{1}{2} \tan \frac{x}{2}\]
=0 if x->0
Well if it is 2+2cosx
OpenStudy (dls):
okay nevermind
OpenStudy (anonymous):
yr its 2-2cosx
OpenStudy (dls):
\[\LARGE \frac{xsinx}{2-2cosx}=\frac{x(x-\frac{x^3}{6})}{2-2(1-\frac{x^2}{2})}=\frac{x^2}{x^2}=1\]
Using series expansions
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OpenStudy (cggurumanjunath):
final answer is 1 if you use LHopital's rule.
OpenStudy (dls):
neglect x^3/6 and other higher order terms
OpenStudy (dls):
when x->0 they tend to 0
OpenStudy (cggurumanjunath):
@dls series answer what you have given above is right answer is 1 but previously xtan(x/2)
answer is zero which is wrong.
OpenStudy (dls):
read properly,he wrote 2+2cosx in the previous reply,so I changed my solution to 2+2cosx in denominator
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