Yes, it is known.
(1) Verification:;
(2) If the value of a is found.
16. (The full score of this small question is 14)
F
As shown in the figure, in a straight triangular prism, is the point on the side (point D is different from point C) and is the midpoint.
E
Verification: (1) plane; [Source: Xue Ke. com]
(2) straight line plane ADE ..
(Question 16)
D
C
A
B
17. (The full score of this small question is 14)
As shown in the figure, establish a plane rectangular coordinate system xOy, where the X axis is on the ground plane, the Y axis is perpendicular to the ground plane, and the unit length is 1 km. A gun is located at the origin of coordinates. It is known that the trajectory of the projectile after launching is on the curve expressed by the equation, where k is related to the launching direction. The range of the gun refers to the abscissa of the impact point of the projectile.
(1) Find the maximum range of the gun;
(2) There is a flying object (regardless of size) in the first quadrant with a flying height of 3.2 kilometers. When the abscissa A does not exceed, how much can a shell hit it? Please explain the reason. [Source: Xue+Ke+Net Z+X+X+K] [Source:]
X (km)
Y km
O
(Question 17)
18. (Full score for this small question 16)
It is known that A and B are real numbers, and 1 and are two extreme points of the function.
(1) Find the values of a and b;
(2) Set the derivative function of the function and find the extreme point;
(3) Let, where the number of zeros of the function is found.
19. (Full score for this small question 16)
A
B
P
O
x
y
(Question 19)
As shown in the figure, in the plane rectangular coordinate system x Oy, the left and right focal points of the ellipse are 0, 0, and both are known on the ellipse, where E is the eccentricity of the ellipse.
(1) Find the eccentricity of the ellipse;
(2) Let A and B be two points on the ellipse above the X axis, and they are straight lines.
Parallel to a straight line and intersecting at point p.
(i) If yes, find the slope of the straight line;
(2) Verification: it is a fixed value.
20. (Full score for this small question 16)
It is known that the sum of two series whose terms are positive satisfies:
(1) hypothesis, verification: the series is arithmetic progression;
(2) Let sum be a geometric series and the value of sum.
This is the general form of the 20 12 college entrance examination, which is similar every year.