3. \mathop {\lim }\limits_{x \to 0}\frac{cosxsinx-tanx}{x^2.sinx}
= \mathop {\lim }\limits_{x \to 0}\frac{sinx(cos^2x-1)}{x^2.sinx.cosx}
=\mathop {\lim }\limits_{x \to 0}\frac{-x^2.(\frac{sinx}{x})^2}{x^2.cosx}
=\mathop {\lim }\limits_{x \to 0}\frac{-1}{cosx}=-1