Question

第6、7题，谢谢了

Answer 1

C(3,-2),r=1,y=x+1,当切线短时,过两切点与圆心C成条直线且与y=x+1平行

K＝1直线y+2=x-3,y=x-5,(x-3)²+(y+2)²=1,(x-3)²+(x-3)²=1,  x-3=+-√2/2

切点坐标:(3+√2/2,-2+√2/2)和(3-√2/2,-2-√2/2),切线与y=x+1垂直Kp＝-1

yp1+2-√2/2=-x+3+√2/2,yp1=-x+1+√2,x1=(√2-1)/2,y1=(√2+1)/2

yp2+2+√2/2=-x+3-√2/2,yp2=-x+1-√2,,x2=-√2/2,y2=1-√2/2,

点P坐标:P(√2-1)/2,√2+1)/2),和(-√2/2,1-√2/2)