20 12 how to do the last math problem in Beijing senior high school entrance examination?

Linear function synthesis of test center; Pythagorean theorem; Theorem of circle angle.

It's hard. My Baidu empty sword has 2 0 12 Beijing senior high school entrance examination questions and analysis ~ ~

Note This topic examines the comprehensive application of functions. The eighth chapter of the third grade intensive promotion class 1 lecture specifically explains this topic. The original title of the senior high school entrance examination is very similar to that given in the handout, and the knowledge points and problem-solving methods are exactly the same.

analyse

(1) ① (0,2) or (0,2)

②

(2)① setting the c coordinate,

Suffer from hell

now

The distance is

At this time.

②

therefore

∴

The minimum value is 1.