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

$\cosh x, \sinh x$ এই গুলো Hyperbolic function.

$f(x)=\cosh x+\sinh x$

$\Rightarrow f(x)=\frac{e^{x}+e^{-x}}{2}+\frac{e^{x}-e^{-x}}{2}$

$\Rightarrow f(x)=\frac{e^{x}+e^{-x}+e^{x}-e^{-x}}{2}$

$\begin{array}{l}\Rightarrow f(x)=\frac{2 e^{x}}{2} \\ \Rightarrow f(x)=e^{x}\end{array}$

$\begin{array}{l}\Rightarrow f\left(x_{1}+x_{2}+x_{3} \cdots \cdot\right)=e^{x_{1}+x_{2}+x_{3} \cdots} \\ \Rightarrow f\left(x_{1}+x_{2}+x_{3} \cdots\right)=e^{x_{1}} \cdot e^{x_{2}} \cdot e^{x_{3}} \cdots \\ \Rightarrow f\left(x_{1}+x_{2}+x_{3} \cdots\right)=f\left(x_{1}\right) \cdot f\left(x_{2}\right) \cdot f\left(x_{3}\right) \cdots\end{array}$