$(2)$ Consider a loaded three$-$hinge arch as shown in Fig. $2,$ in which EI$=$constant,

$($a$)$ Determine the reaction forces $(V_A,H_A)$ at point $A,(V_B,H_B)$ at point $B,$ the internal forces $(V_{c^{-}},V_{c^{+}},H_c)$ at

the center hinge $C$;

$($b$)$ Draw the internal axial force, shear force, and bending moment diagrams of member DC$.$