In Problems, sketch the graph of the given function over the interval [a, b]; then divide [a, b] into n equal subintervals Finally, calculate the area of the corresponding circumscribed polygon.
(a). f(x) = x + 1; a = -1, b = 2, n = 3
(b). f(x) = 3x - 1; a = 1, b = 3, n = 4
(c). f (x) = x2 - 1; a = 2, b = 3, n = 6