* $\mathop {\lim }\limits_{x \to 0}(\frac{x-\sin x}{x^2.\sin x})=\mathop {\lim }\limits_{x \to 0}(\frac{1-\cos x}{2x\sin x+x^2\cos x})=\mathop {\lim }\limits_{x \to 0}(\frac{x^2}{2x^2(2\frac{\sin x}{x}+\cos x)})=\frac{1}{6}$* $\mathop {\lim }\limits_{x \to 0}(\frac{x-(x-\frac{x^3}{3!}+\theta (x^3))}{x^3})=\frac{1}{6}$