(2) If A(3,-1) and -(3-h) 2+0 =- 1 are substituted, the solution is H=2 or 4.

When H=2 and Y =-(x-2) 2, the linear function of P (2,0) solution is Y =-x+2;

When H=4 and y =-(x-4) 2, then P (4,0), the linear function is y=x-4 (excluding).

(3) When H=2, Pa 2 = 2, Pb 2 = 20 and AB 2 =18, then △PAB is a right triangle ∠ A 90.

So sin∠PBA=PA/PB= root number 10/ 10.

2.( 1) is equal, which proves that △ Abe △ CBG;

(2) It is easy to prove △ABE∽△DEH, and x/y= 1/( 1-x), that is, y =-x 2+x, so when x= 1/2, y is the largest.

(3) from the triangle BEH∽ triangle BAE, EH/AE=BE/BA, that is, [y 2+(1-x) 2]/x 2 = (1+x 2)1,x is obtained.