Write a PYTHON program in a script file that evaluates the derivative of the function $f(x)=x^{3}cosx$

at the point $x=3.$ The value of the derivative is calculated sixteen times by using

$a=3$ and sixteen values of $x,x=2\mathrm{.}6,2\mathrm{.}65,..,2\mathrm{.}95,3\mathrm{.}05,..,3\mathrm{.}35,3\mathrm{.}4.$ The program should also plot the

values of the derivative versus $x.$

To calculate the derivative at $x=a=3,$ use $"(f(3\mathrm{.}05)-f(2\mathrm{.}95))/(3\mathrm{.}05-$

$2\mathrm{.}95.$