=

24 cm

，AB

=

8 cm

, BC

=

26 cm

The moving point p starts from point a and is 1cm along the AD direction.

/

s

Moving at the speed of, the moving point q is 3cm from point C along the edge of CB to point B.

/s

The moving speed, P and Q, starts from A and C respectively at the same time. When one point moves to the end point, the other point stops moving. Let the moving time be T.

Second,

t

When the value is, the quadrilateral PQCD is: (1) parallelogram? (2) isosceles trapezoid?

2. As shown in the figure, in △ABC

Where point O is the moving point on the side of AC, and the intersection point O is the straight line MN ∠ BC, let the angular bisector of Mn ∠BCA be at point E and the external angular bisector of Mn ∠BCA be at point F. 。

(1) verification: EO = FO

(2) When the point O moves to where, the quadrilateral AECF is a rectangle? And prove your conclusion.

3. In the known parallelogram ABCD, point E and point F are on the AB side and BC side respectively.

(1) If AB= 10, the distance between AB and CD is 8, AE=EB, BF=FC, find the area of △DEF.

(2) If the areas of △ADE, △BEF and △CDF are 5, 3 and 4 respectively, find the area of △DEF.

4, as shown in the figure, straight line

and

Axis,

The axes intersect at point A and point B respectively, and m is a point on OB. If △ABM is folded along AM, point B falls right on it.

Point on the axis

The analytical formula of the straight line AM is

5. In order to alleviate the shortage of electricity consumption, a power company has specially formulated a new charging standard for electricity consumption, that is, monthly electricity consumption.

(degree) and electricity payable

The relationship between (meta) is shown in the figure.

(1) According to the picture, please find out.

and

When,

and

Function relation of.

(2) Please answer: When the monthly electricity consumption does not exceed 50 degrees, the charging standard is _ _ _ _ _ _; When the monthly electricity consumption exceeds 50 degrees, the charging standard is

6. As shown in the figure, straight line

and

Axis,

The intersection points of the axes are point B and point A respectively, point C is the midpoint of OA, and a ray cm ⅹ is made to the left after passing through point C..

Axis and point D are moving points on line segment OB, which are not coincident with point B. DP⊥CM is at point P, and DE⊥AB is at point E, connecting PE.

(1) Find the coordinates of points A, B and C;

(2) The abscissa of point D is

Delta bed area is s, so find s.

Function relation of;

(3) Is there a point D that makes △DPE an isosceles triangle? If yes, please write down all the requirements directly.

The value of; If it does not exist, explain why.

7. (The full mark of this question is 12) As shown in the figure, in Rt△ABC, AB=AC, and P is the moving point (including the end point) on the side of AB. P is the vertical line PR of BC, R is the vertical foot, the bisector of ∠PRB intersects with AB at point S, and there is a point T on the line segment RS. If a square PTEF is made with the line segment PT as one side,

Whether (1)△ABC and△△ SBR are similar, and explain the reasons;

(2) Please explore the relationship between the length of segment TS and PA;

(3) Let AB= 1. When P moves to the AB side (including the end point), please explore the minimum and maximum values of the area y of the square PTEF.