find the limit x-->0+ of f(x) = sin(x) ln(x) thanks
M mathhelp New member Joined Nov 12, 2006 Messages 25 Dec 17, 2006 #1 find the limit x-->0+ of f(x) = sin(x) ln(x) thanks
skeeter Elite Member Joined Dec 15, 2005 Messages 3,216 Dec 17, 2006 #2 \(\displaystyle \L \lim_{x \rightarrow 0^+} \sin{x} \ln{x} =\) \(\displaystyle \L -\lim_{x \rightarrow 0^+} \frac{-\ln{x}}{\csc{x}}\) as x -> 0<sup>+</sup>, both numerator and denominator approach infinity ... use L'Hopital's rule. \(\displaystyle \L -\lim_{x \rightarrow 0^+} \frac{-\frac{1}{x}}{-\csc{x}\cot{x}}=\) \(\displaystyle \L -\lim_{x \rightarrow 0^+} \frac{\sin{x}\tan{x}}{x}=\) \(\displaystyle \L -\lim_{x \rightarrow 0^+} \frac{\sin{x}}{x}\tan{x}= -1 \cdot 0 = 0\)
\(\displaystyle \L \lim_{x \rightarrow 0^+} \sin{x} \ln{x} =\) \(\displaystyle \L -\lim_{x \rightarrow 0^+} \frac{-\ln{x}}{\csc{x}}\) as x -> 0<sup>+</sup>, both numerator and denominator approach infinity ... use L'Hopital's rule. \(\displaystyle \L -\lim_{x \rightarrow 0^+} \frac{-\frac{1}{x}}{-\csc{x}\cot{x}}=\) \(\displaystyle \L -\lim_{x \rightarrow 0^+} \frac{\sin{x}\tan{x}}{x}=\) \(\displaystyle \L -\lim_{x \rightarrow 0^+} \frac{\sin{x}}{x}\tan{x}= -1 \cdot 0 = 0\)