Answer
$$0$$
Work Step by Step
Given
$$\lim _{x \rightarrow \infty}\sqrt{x}\sin\frac{1}{x}$$
Then
\begin{aligned}
\lim _{x \rightarrow \infty}\sqrt{x}\sin\frac{1}{x}&=\lim _{x \rightarrow \infty}\sqrt{x}\sin\left(\frac{1}{x}\right)\frac{1/x}{1/x} \\
&=\lim _{x \rightarrow \infty}\frac{1}{\sqrt{x}}\frac{\sin\left(\frac{1}{x}\right)}{1/x}\\
&=\lim _{x \rightarrow \infty}\frac{1}{\sqrt{x}}\lim _{x \rightarrow \infty}\frac{\sin\left(\frac{1}{x}\right)}{1/x}\\
&=(0)(1)\\&=0
\end{aligned}