\[ \lim _{x \rightarrow 0} \frac{2 x+x^{2}}{\sin 3 x} \] \( \lim _{\theta \rightarrow 0} \frac{\theta+\sin \theta}{\theta-\sin \theta} \) \[ \lim _{h \rightarrow 0} \frac{1-\cos h}{h^{2}} \]