Hello, I need help with this problem. Thanks in advance.

Suppose we divide the interval [ 1, 4] into 100 equally wide subintervals and calculate a Riemann sum for f(x ) = 1 + x- - by randomly selecting a point c; in each subinterval. We can be certain that the value of the Riemann sum is within what distance of the exact value of the area between the graph of f and the interval [ 1, 4] ? (b) What if we take 200 equally long subintervals