Create a user-defined function f(x) that returns the value 1 + tanh 2x, then use a central difference to calculate the derivative of the function in the range -2 x 2. Calculate an analytic formula for the derivative and make a graph with your numerical result and the analytic answer on the same plot. It may help to plot the exact answer as lines and the numerical one as dots. (Hint: In Python the tanh function is found in the math package, and it's called simply tanh.)