Inverse calculation of p coordinate;
Quadrilateral PAM has the smallest area-triangular PAM has the smallest area-PA has the smallest length-PM has the smallest length.
The minimum length of PM is 2.
Let p (x, y) and y 2 = 4x.
The length of PM2 = (x-3) 2+Y2 = (x-3) 2+4x = x2-2x+9 is the smallest.
x= 1
P( 1,2)
Calculate the coordinates of A and B forward, and then calculate the AB equation (or calculate the slope first by using the vertical relationship between AB and PM to simplify the calculation).
The calculation is simplified.