C
D
X
O
P
A
Y
23.( 1 1) As shown in the figure, in the plane rectangular coordinate system, a straight line intersects a parabola at two points, point A is on the axis, and the ordinate of point B is 3. Point P is a moving point on the parabola below straight line AB (which does not coincide with A and B), and the intersection of the vertical line with point P and point C is PD ⊥.
(1).
(2) The abscissa of point P is
① The length of line segment PD is expressed by algebraic expression,
And find out the maximum length of the line segment PD;
② Connect PB and divide the line segment PC into two parts.
Whether the two triangles have proper values,
Make the area ratio of these two triangles 9: 10?
If it exists, write the value directly; If it does not exist, explain why.
23, (1) times to get ⅷ.
Get ⅷ from
After two points,
∴
Let a straight line intersect the axis at a point, and then
∑ axis, ∴
∴
(2) According to (1), the analytical formula of parabola is
∴
Yes,
At the right time, there is a maximum.
(2) there are values that meet the conditions,
point out
The ones passing through point D and point B respectively are DF⊥PC, and the vertical feet are F and G respectively.
Yes,
and
∴
When? solve
When will it be solved?