For your reference
Midline rule? Let (x,y)-center be the middle line
那個2^2是為什麼？
謝謝你的圖
但是我還是不知道2^2是在算哪裡？
The middle point (x,y) between any point on the circle and the point P. 2 is the radius that is distance between any point and the center of the circle.
請問第一個式子等號後的
1/2(2^2+根號20^2)是指什麼？