Let the resolution function of parabola be y=ax2,
The coordinates of point A are (4,8).
Point a is on a parabola,
∴8=a×42,
Solve a=,
The resolution function of parabola is: y = x2.
(2) find a way to:
Extend AC, pass through the parabola of the building shape at point D,
Then point a and point d are symmetrical about OC.
Connect BD and OC at point P, then point P is what you want.
(3) According to the meaning of the question, the abscissa of point B is 2.
Point b is on a parabola,
∴ The coordinates of point B are (2,2),
Similarly, the coordinate of point A is (4,8),
The coordinate of point ∴d is (∴ 4,8),
Let the resolution function of straight line BD be y=kx+b,
∴ ,
Solution: k =- 1, b = 4.
The resolution function of the straight line BD is y = x+4,
Substitute x=0 into y =-x+4, and the coordinate of point P is (0,4).
The materials used for the two columns are the most time-saving, and the distance between point O and point P is 4m. Agree 67| Comment (33)