If $f(x)=\cosh x+\sinh x$ then $f(x_{1}+x_{2}+.......+x_{n})=$

Let $f(x)=\left | x-x_{1} \right |+\left | x-x_{2} \right |$ where $x_{1} and x_{2}$ are distinct  real numbers. Then the number of points at which f(x) is minimum is:

If $x = (7 + 4\sqrt {3})^{2n} = [x] + f$, where $n \epsilon N$ and $0\leq f < 1$, then $x(1 - f)$ is equal to

$f(x)=\sin x$

$\frac{f\left(\frac{\pi}{10}\right)+f\left(\frac{\pi}{2}-\frac{\pi}{10}\right)}{f\left(\frac{\pi}{2}-\frac{3 \pi}{20}\right)}$ এর মান কত?