The number of points of discontinuity of $f(x)$ where $f(x) = | | |x + [x]| - 3[x] | - 5[x] |$ on $[-2, 2]$ is (where $[ \cdot ]$ denotes the greatest integer function).

If $f: R \rightarrow R$ defined by $f(x) = \begin{cases} a^2 \cos ^2 x+b^2 \sin ^2 x, & x \leq 0 \\ e^{ax+b}, & x>0 \end{cases}$ is a continuous function, then:

Statement $1$: $A$ function $f: R \to R$ is continuous at $x_0$ if and only if $\lim_{x \to x_0} f(x)$ exists and $\lim_{x \to x_0} f(x) = f(x_0)$.
Statement $2$: $A$ function $f: R \to R$ is discontinuous at $x_0$ if and only if $\lim_{x \to x_0} f(x)$ exists and $\lim_{x \to x_0} f(x) \neq f(x_0)$.

If $f(x) = \begin{cases} \log(\sec^2 x)^{\cot^2 x}, & x \neq 0 \\ K, & x = 0 \end{cases}$ is continuous at $x = 0$,then $K$ is

If $f(x) = \begin{cases} \frac{8^x-4^x-2^x+1}{x^2}, & \text{if } x > 0 \\ e^x \sin x + x + \lambda \log 4, & \text{if } x \leqslant 0 \end{cases}$ is continuous at $x = 0$,then the value of $1000 e^\lambda = $

Prove that every rational function is continuous at every point in its domain.