Add methods to compute and plot using the [trapezoidal rule](https://en.wikipedia.org/wiki/Trapezoidal_rule). Hint: "The trapezoidal rule may be viewed as the result obtained by averaging the left and right Riemann sums, and is sometimes defined this way."
Add methods to compute and plot using the trapezoidal rule.
Hint: "The trapezoidal rule may be viewed as the result obtained by averaging the left and right Riemann sums, and is sometimes defined this way."