A fixed-end beam AB of length L is subjected to a uniform load of intensity q acting

Question:

A fixed-end beam AB of length L is subjected to a uniform load of intensity q acting over the middle region of the beam (see figure).
(a) Obtain a formula for the fixed-end moments MA and MB in terms of the load q, the length L, and the length b of the loaded part of the beam.
(b) Plot a graph of the fixed-end moment MA versus the length b of the loaded part of the beam. For convenience, plot the graph in the following nondimensional form:

with the raio b/L varying between its extreme values of 0 and 1.
(c) For the special case in which a = b - L/3, draw the shear-force and bending-moment diagrams for the beam, labeling all critical ordinates.