[问答题]
A circle of radius 3 and centre (0,3) is drawn on an Argand d-;k e.u+k jkm bct0*+6cgw9o7hifei jiagram. The tang1)68p3 hi4dcawfb8 fzh7k uisent to the circle from the point B(0,9) meets the circle at the point A as shown. Lefshfa6 8k hcpi14)b3id7 zwu8t $w=\overrightarrow{\mathrm{OA}}$
