28.62. Calculate the limit $\lim _{x \rightarrow 0} \frac{\tan x - x}{x - \sin x}$.

### 28.10. The number of roots of the equation
28.62. Answer: 2. Transform the ratio of derivatives:

$$
\frac{\frac{1}{\cos ^{2} x}-1}{1-\cos x}=\frac{1}{\cos ^{2} x} \cdot \frac{1-\cos x^{2}}{1-\cos x}=\frac{1+\cos x}{\cos ^{2} x}
$$

The last expression tends to 2 as $x \rightarrow 0$.