题目内容
如图,AB为⊙O的直径,AC为⊙O的弦,AB=2,AC=,D为圆上一点,若AD=,则∠DAC= .
15 °或75°
如图,AB为⊙O的直甲径,PD切⊙O于点C,交AB的延长线于D,且CO=CD,则∠PCA=
A.60°
B.65°
C.67.5°
D.75°