∴ Substitute X = 0 and Y = 0 respectively to get a (0,3) and c (4,0).
AB = AC
∴OB=OC
Yes, b (-4,0)
ABCD is a parallelogram.
∴AD=BC
De, D (8,3)
Substitute the coordinates of b and d into y= 1/8x2+bx+c,
0=2-4b+c
3=8+8b+c
The solution is b =- 1/4 and c =-3.
∴y= 1/8x2- 1/4x-3
(2)
① When PQ⊥AC
△AOC∽△PQA
Associated Press: AQ = California: Co.
PQ⊥AC when t seconds are set.
T: (5-t) = 5: 4。
t=25/9
P(25/9,3)
(2) Let the coordinates of point P be (t, 3), and point Q be the QH⊥x axis intersecting with AD and the X axis intersecting with M in H.
Then SPDCQ = s △ ACD-s △ APQ =1/2ad× ao-1/2ap× qh =1/2× 8× 3-1/2ap× (hm-QM).
= 12- 1/2ap×(OA-QM)= 12- 1/2ap×(OA-3/5QC)
= 12- 1/2t(3-3/5t)= 12- 1.5t+0.3t 2 = 0.3(t-2.5)2+ 10. 125
So when t=2.5, the area is the smallest, that is, P (2.5,3).
Minimum area = 10. 125