Let f(x)= lim_y → 0 ((1- cos (x y)) tan (x y))/y^3. Then the number of solutions of the equation f(x)= sin x, x ∈ R is:

Let $\displaystyle f(x)=\lim _{y \rightarrow 0} \frac{(1-\cos (x y)) \tan (x y)}{y^3}$. Then the number of solutions of the equation $\displaystyle f(x)=\sin x$, $\displaystyle x \in \mathbf{R}$ is :