1) Cho tam giac ABC co CD la tia phan giac goc BCA va C thuoc canh AB. Thi khang dinh nao sau day la dung
A. \(\dfrac{CA}{DB}=\dfrac{DA}{CB}\) B. \(\dfrac{CB}{CA}=\dfrac{DA}{DB}\) C. \(\dfrac{CA}{CB}=\dfrac{DB}{DA}\) D. \(\dfrac{CA}{CB}=\dfrac{DA}{DB}\)
Chọn D