Let f be a differentiable function such that f^′(x)=7-3/4 (f(x))/x,(x>0) and f(1) ≠ 4. Then lim_x → 0^+ x f(1/x):

Let $\displaystyle f$ be a differentiable function such that $\displaystyle f^{\prime}(x)=7-\frac{3}{4} \frac{f(x)}{x},(x>0) \quad$ and $\displaystyle f(1) \neq 4$. Then $\displaystyle \lim _{x \rightarrow 0^{+}} x f\left(\frac{1}{x}\right)$ :