(2) Because the abscissa of point B is 1 and the ordinate is 2, B( 1, 2).

Because the intersection with the proportional function y= 1/2x is a,

So simultaneous equations: y=2/x, y= 1/2 x, x=2, y= 1 or x=-2, y =-1; So A(2, 1).

Let point A (2, 1) be the symmetrical point A'(2,-1) about the X axis, connect A'b, and intersect with the X axis at point P, where point P is the demand and PA+PB is the minimum;

If you want the coordinates of point p, you can first find the analytical expression of straight line A'b, and then find the intersection of A'b and X axis.

2.( 1)y 1=-2x passes through point P(-2, a), so P(-2, 4),

Because point P' and point P are symmetrical about Y axis, P' (2,4)

(2) Because the point p' is on the image of inverse proportional function y2=k/x(k≠0). So y2= 8/x,

X>4 or X.