Answer
$\frac{1}{2}$
Work Step by Step
$\lim_{r\to0}\frac{sin(r)}{tan2r}=\lim_{r\to0}\frac{sin(r)cos2r}{sin2r}=\lim_{r\to0}\frac{sin(r)cos2r}{2sin(r)cos(r)}=\lim_{r\to0}\frac{cos2r}{2cos(r)}=\frac{1}{2}$
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