SOLUTION 6:   $$     \displaystyle{  \lim_{x \rightarrow 0} \frac{ x \tan x }{ \sin 3x }   } = 
\displaystyle{   \frac{ 0 \cdot \tan(0) }{ \sin(0) }   } = \displaystyle{   \frac{ 0 \cdot 0 }{ 0 }   } = \frac{"0"}{0} $$ 
(Apply Theorem 1 for l'Hopital's Rule.  Differentiate top and bottom separately.  Use the Product Rule on the top.  Use the Chain Rule on the bottom.)
$$ =   \displaystyle{  \lim_{x \rightarrow 0} \frac{ x \sec^2 x + (1) \tan x  }{ 3 \cos x }   }  $$
$$ =   \displaystyle{   \frac{ (0) \sec^2(0) +  \tan(0)  }{ 3 \cos(0) }   }  $$
$$ =   \displaystyle{   \frac{ (0)(1)^2 + 0  }{ 3 (1) }   }  $$
$$ =   \displaystyle{   \frac{ 0 }{ 3 } } $$
$$ =   \displaystyle{ 0 } $$
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