C.a.R. > Applications > Area > Riemann Integral
The function x^2 is displayed and integrated in two different ways. First with the maximal accuracy achieved by C.a.R., then as a sum. In this case, the Riemann sum could have been computed by a simple formula.
C.a.R uses the Romberg procedure to integrate. For discrete functions, it uses a Riemann sum. The display of a discrete, filled function reflects this sum.