Then the positional relationship between the straight line x0x+y0y = a 2 and this circle is

Point M(x0, y0) is a circle x 2+y 2 = a 2 (a > 0), a point different from the center of the circle.

So x0 2+y0 2 < a 2.

Line x0x+y0y = The distance from the center of the circle is 2.

d=|0+0-a^2|/√(x0^2+y0^2)>； a^2/a=a

I.e. greater than the radius.

The positional relationship is separation.