Lines l and o are tangent to point c,

∴OC⊥l，

∵AD⊥l，

∴OC∥AD，

∴∠OCA=∠DAC，

OA = OC，

∴∠BAC=∠OCA，

∴∠bac=∠dac=30；

(2) As shown in Figure ②, connect BF,

∵AB is the diameter⊙ O,

∴∠AFB=90，

∴∠BAF=90 -∠B，

∴∠aef=∠ade+∠dae=90+ 18 = 108

In ⊙O, the quadrilateral ABFE is the inscribed quadrilateral of a circle,

∴∠AEF+∠B= 180，

∴∠B= 180 - 108 =72，

∴∠BAF=90 -∠B=90 -72 = 18。