∵ The beam is symmetrical with antisymmetrical loading, we can write :
KBA=3EI6;KBC=6E(2I)6
DFBA=0.2;DFBC=0.8
MBA=67.5+3EI6θB=54
⇒θB=−27EI
MAB=−5×24×6296+2EI6[2θA+θB]=0
⇒θA=0.0196 rad