For real constants $a$ and $b$, let \[ f(x) = \begin{cases} \frac{a \sin x - 2x}{x}, & x < 0 \\ bx, & x \ge 0 \end{cases} \]
If $f$ is a differentiable function, then the value of $a + b$ is
If $\{x_n\}_{n \ge 1}$ is a sequence of real numbers such that $\lim_{n \to \infty} \frac{x_n}{n} = 0.001$, then
The value of
is
If f(x) = \(\left\{ \begin{aligned} & \frac{1-\cos Kx}{x\sin x} ,\ \ \text{if x}\neq0 \\ &\ \ \ \ \ \ \ \frac{1}{2}\ \ \ \ \ \ \ \ \ ,\ \ \ \text{if x=0} \end{aligned} \right.\) is continuous at x = 0, then the value of K is