一、选择题答案

1. 【答案】A
2. 【答案】B
3. 【答案】C
4. 【答案】D
5. 【答案】A
6. 【答案】C
7. 【答案】B
8. 【答案】D
9. 【答案】C
10. 【答案】B
二、填空题答案
11. 【答案】(1)2
(2)2
(3)π/2
(4)1/2
(5)√3
12. 【答案】(1)5
(2)8
(3)2
(4)3
(5)1/2
三、解答题答案
13. 【答案】(1)设等差数列{an}的公差为d,由题意得
a1 = 3
a5 = 8
所以,2d = a5 - a1 = 8 - 3 = 5
因此,d = 5/2
则an = a1 + (n - 1)d = 3 + (n - 1)×(5/2)
化简得,an = 3 + 5n/2 - 5/2 = 5n/2 - 2/2
所以,第n项为an = 5n/2 - 1
(2)设等比数列{bn}的首项为b1,公比为q,由题意得
b1 = 1
b4 = 81
所以,q^3 = b4 / b1 = 81 / 1 = 81
因此,q = 3
则bn = b1 * q^(n - 1) = 1 * 3^(n - 1)
化简得,bn = 3^(n - 1)
14. 【答案】(1)设函数f(x) = ax^2 + bx + c的对称轴为x = k,则k = -b/(2a)
由题意得,k = -1,所以 -b/(2a) = -1
化简得,b = 2a
(2)将x = 0代入f(x),得f(0) = c = 0
将x = -1代入f(x),得f(-1) = a - b + c = -1
将x = 1代入f(x),得f(1) = a + b + c = 3
解方程组
a + b + c = 3
a - b + c = -1
解得a = 1,b = 1,c = 1
所以,函数f(x) = x^2 + x + 1
(3)因为a = b = 1,所以函数f(x)的图像为开口向上的抛物线,对称轴为x = -1/2
当x < -1/2时,函数f(x)的值单调递增;当x > -1/2时,函数f(x)的值单调递减
所以,函数f(x)的最大值为f(-1/2) = 3/4
四、压轴题答案
15. 【答案】(1)设点A在直线x - 2y - 2 = 0上,则A的坐标为(x1, y1),满足x1 - 2y1 - 2 = 0
点B在直线2x - y + 2 = 0上,则B的坐标为(x2, y2),满足2x2 - y2 + 2 = 0
点C在直线x + 3y - 3 = 0上,则C的坐标为(x3, y3),满足x3 + 3y3 - 3 = 0
点D在直线3x + y - 3 = 0上,则D的坐标为(x4, y4),满足3x4 + y4 - 3 = 0
(2)点A在直线x - 2y - 2 = 0上,所以x1 = 2y1 + 2
点B在直线2x - y + 2 = 0上,所以y2 = 2x2 + 2
点C在直线x + 3y - 3 = 0上,所以x3 = 3 - 3y3
点D在直线3x + y - 3 = 0上,所以y4 = 3 - 3x4
(3)设直线AB的方程为y = kx + m,代入A、B两点的坐标得
y1 = kx1 + m
y2 = kx2 + m
联立上述两个方程,得
k = (y2 - y1) / (x2 - x1)
m = y1 - kx1
化简得直线AB的方程为y = (2y1 + 2 - 2x2 - 2) / (x2 - x1)x + (x1y2 - x2y1) / (x2 - x1)
(4)设直线CD的方程为y = kx + n,代入C、D两点的坐标得
y3 = kx3 + n
y4 = kx4 + n
联立上述两个方程,得
k = (y4 - y3) / (x4 - x3)
n = y3 - kx3
化简得直线CD的方程为y = (3 - 3y3) / (x3 - x4)x + (x3y4 - x4y3) / (x3 - x4)
(5)根据题意,点A在直线x - 2y - 2 = 0上,点B在直线2x - y + 2 = 0上,点C在直线x + 3y - 3 = 0上,点D在直线3x + y - 3 = 0上
由(1)可得,A的坐标为(x1, y1),B的坐标为(x2, y2),C的坐标为(x3, y3),D的坐标为(x4, y4)
将A、B、C、D的坐标代入直线AB和直线CD的方程,得
直线AB的方程为y = (2y1 + 2 - 2x2 - 2) / (x2 - x1)x + (x1y2 - x2y1) / (x2 - x1)
直线CD的方程为y = (3 - 3y3) / (x3 - x4)x + (x3y4 - x4y3) / (x3 - x4)
(6)根据(5),直线AB和直线CD的方程为
直线AB:y = (2y1 + 2 - 2x2 - 2) / (x2 - x1)x + (x1y2 - x2y1) / (x2 - x1)
直线CD:y = (3 - 3y3) / (x3 - x4)x + (x3y4 - x4y3) / (x3 - x4)
(7)因为点A在直线AB上,点C在直线CD上,所以A、C两点坐标分别代入直线AB和直线CD的方程,得
直线AB:y1 = (2y1 + 2 - 2x2 - 2) / (x2 - x1)x1 + (x1y2 - x2y1) / (x2 - x1)
直线CD:y3 = (3 - 3y3) / (x3 - x4)x3 + (x3y4 - x4y3) / (x3 - x4)
(8)由(7)可得
y1 = (2y1 + 2 - 2x2 - 2) / (x2 - x1)x1 + (x1y2 - x2y1) / (x2 - x1)
y3 = (3 - 3y3) / (x3 - x4)x3 + (x3y4 - x4y3) / (x3 - x4)
(9)将y1、y3代入直线AB和直线CD的方程,得
直线AB:y = (2y1 + 2 - 2x2 - 2) / (x2 - x1)x + (x1y2 - x2y1) / (x2 - x1)
直线CD:y = (3 - 3y3) / (x3 - x4)x + (x3y4 - x4y3) / (x
