Solve analytically and by finite difference by using matlab

$1)$Discretizing the differential equation

$2)$Simplify to the form Ax $=$ b

$3)$ Matlab solution for x

A fin of diameter $0\mathrm{.}02m$ and length $0\mathrm{.}08m$ is attached to a wall. The temperature at the wall is $200C.$ Determine the temperature of the fin at $x=0\mathrm{.}02,0\mathrm{.}04,0\mathrm{.}06$ and $0\mathrm{.}08m,$ using finite difference technique taking four parts. The thermal conductivity of the rod is $25\frac{W}{m}K$ and convective heat transfer coefficient from rod to surroundings is $40\frac{W}{m^2}K.$ The governing differential equation is

$-\frac{d^2}{d{x}^2}+\frac{hP}{kA}=0,$ where $=T-T_{\text{s}\text{u}\text{r}\text{r}}=T-25,$

and the boundary condition at $x=0\mathrm{.}08m$ is $\frac{d}{dx}+\frac{h}{k}=0.$