(2) By knowing A (- 1, 0) and B (3,0), let the functional expression of BC line be, and substitute it into point B (3,0) and point C (0,3) to get the solution. So the functional expression of BC line is.
(3)① Since AB = 4, since P and Q are symmetrical about the straight line X = 1, the abscissa of point P is. In this way, the coordinates of point p and point f are obtained.
In addition, the coordinates of point e are.
Line BC: The coordinate of the intersection of D and parabola symmetry axis X = 1 is (1, -2).
The intersection d is DH⊥y axis, and the vertical foot is H.
In Rt△EDH, DH = 1, so tan ∠ ced.
② , .
Figure 2 Figure 3 Figure 4