Add methods to compute and plot using the [Simpson's rules](https://en.wikipedia.org/wiki/Simpson%27s_rule). Hint: There is a [simple form](https://en.wikipedia.org/wiki/Simpson%27s_rule#Averaging_the_midpoint_and_the_trapezoidal_rules) based on trapezoidal rule and Riemann's midpoint.
Add methods to compute and plot using the Simpson's rules.
Hint: There is a simple form based on trapezoidal rule and Riemann's midpoint.