How to calculate this limit:
$$\lim_{x\rightarrow 0}\left(\frac{1}{x}-\frac{1}{\sin x}\right)$$
All I know is:
$$\lim_{x\rightarrow 0} \frac{\sin x}{x} = 1$$
$$\lim_{x\rightarrow 0} \, x = 0$$
$$\lim_{x\rightarrow 0} \,\sin x = 0$$
How to calculate this limit:
$$\lim_{x\rightarrow 0}\left(\frac{1}{x}-\frac{1}{\sin x}\right)$$
All I know is:
$$\lim_{x\rightarrow 0} \frac{\sin x}{x} = 1$$
$$\lim_{x\rightarrow 0} \, x = 0$$
$$\lim_{x\rightarrow 0} \,\sin x = 0$$
Hint: Write it as $$\lim_{x\to0}\dfrac{\sin x-x}{x\sin x},$$ and apply L'Hôpital's rule twice.
Hint: $\dfrac{1}{x} - \dfrac{1}{\sin x} = \dfrac{\sin x - x}{x\sin x}$, and use L'hopitale rule !