如图所示,△ABC中,∠ACB＞90°,AE平分∠BAC,AD垂直于BC交BC的延长线于点D,则∠DAE,∠ACB,∠B

∠DAE=1/2(∠ACB-∠B)∠ADB=90度∠ACB=∠ADB+∠DAC所以∠ACB=90-∠DAC因为∠ADB+∠DAB+∠B=180度∠DAB=∠DAE+∠BAE所以∠DAE+∠BAE+∠B=90度因为AE平分∠BAC所以∠CAE=∠BAE∠CAE+∠DAC=∠DAE所以∠BAE=∠DAE-∠DAC所以∠ACB=∠DAE+∠DAE-∠DAC+∠B+∠DAC∠ACB=2∠DAE+∠B所以∠DAE=1/2(∠ACB-∠B)