延长BA,做PN⊥BD,PF⊥BA,PM⊥AC,设∠PCD=x°,∵CP平分∠ACD,∴∠ACP=∠PCD=x°,PM=PN,∵BP平分∠ABC,∴∠ABP=∠PBC,PF=PN,∴PF=PM,∵∠BPC=40°,∴∠ABP=∠PBC=（x-40）°,∴∠BAC=∠ACD-∠ABC=2x°-（x°-40°）-（...角BPC和角BAC的关系两倍