4. The figure shows a simply supported beam. The beam is subjected to two uniformly distributed (rectangular) forces, one uniformly increasing (triangular) distributed force, a point force, and a couple moment. a. Determine the support reactions at the supports A and B. b. Find the shear-force and bending-moment equations in the region between points B and C (i.e., region with the triangular force), as a function of the distance "x," measured from the left end of the beam. Do not use the shortcut method in this part. c. Draw the shear-force and bending-moment diagrams for the entire beam. Label all critical points (local minima, local maxima, x-crossings, etc.). You can use the shortcut method in this part. d. Determine the following critical location(s) in the beam (if they exist): a. Where the shear force is zero, b. Where the bending moment is zero, c. Where the shear force is maximum (also specify the value of the shear force at this location), d. Where the bending moment is maximum (also specify the value of the bending moment at this location). A 18 m 18 kN 6 kN/m 515 kNm B 6 kN/m C 7 m 4 m 6 kN/m 14 m 6 m 7 m + 9 m