1 圆C：(x-2)^2+(y-3)^2=1 设切点为P(x,y),向量CP=(x-2,y-3),向量AP=(x-3,y-5)所以(x-2,y-3)(x-3,y-5)=0即(x-2)(x-3)+(y-3)(y-5)=0 y=3或x=7/5，y=14/5即P(3,3)或P(7/5,14/5)x=3或11 x-8y+7=02AOC的面积S=0.5
