X^2+Y^2=1圆上任意一点Q(x0,y0)
OQ的斜率=y0/x,
0Q点切线方程y-y0=-x0/y0(x-x0)
y*y0-y0^2=-x*x0+x0^2
x*x0+y*y0=x0^2+y0^2
x*x0+y*y0=1
MA MB切点为(x1,y1)(x2,y2)
则x*x1+y*y1=1,x*x2+y*y2=1
将M点代入上式得3*x1+2*y1=1,3*x2+2*y2=1
所以所求方程 3x+2y-1=0
X^2+Y^2=1圆上任意一点Q(x0,y0)
OQ的斜率=y0/x,
0Q点切线方程y-y0=-x0/y0(x-x0)
y*y0-y0^2=-x*x0+x0^2
x*x0+y*y0=x0^2+y0^2
x*x0+y*y0=1
MA MB切点为(x1,y1)(x2,y2)
则x*x1+y*y1=1,x*x2+y*y2=1
将M点代入上式得3*x1+2*y1=1,3*x2+2*y2=1
所以所求方程 3x+2y-1=0