Current location - Information Consultation Platform - Consulting Services - (2008? Jingzhou) as shown in the figure, in the plane rectangular coordinate system, point A is in the first quadrant, ⊙A is tangent to X axis B, and intersects Y axis at C (0, 1), D (0, 4.

(2008? Jingzhou) as shown in the figure, in the plane rectangular coordinate system, point A is in the first quadrant, ⊙A is tangent to X axis B, and intersects Y axis at C (0, 1), D (0, 4.

Solution: pass point a as AM⊥CD.

∵⊙A is tangent to the X axis at point B, and intersects the Y axis at points C (0, 1) and D (0 0,4).

∴oc= 1,cd=3,dm=cm= 1.5

∴OM=AB=2.5，

The radius of the circle R=2.5,

∴AC=2.5

∴AM=AC2？ CM2=2，

That is, the coordinate of point A is (2,52).

So choose C.