2(x2?x1)?x2?x1?2m,2[(x2?x1)?2x2x1]?x2?x1?2m,2m?3,m?二、填空题 1.(?2223 23535,) 可以证明PF1?a?ex,PF2?a?ex,且PF12?PF22?F1F22 555,则(a?ex)2?(a?ex)2?(2c)2,2a2?2e2x2?20,e2x2?1 3而a?3,b?2,c?5,e?x2?1113535,??x?,即 ??e?e2ee55115 渐近线为y??tx,其中一条与与直线2x?y?1?0垂直,得t?,t?
2422.x25 ?y2?1,a?2,c?5,e?42?y2?8x4k?83.215 ?,k2x2?(4k?8)x?4?0,x1?x2??4 2k?y?kx?22得k??1,或2,当k??1时,x?4x?4?0有两个相等的实数根,不合题意
当k?2时,AB?1?k2x1?x2?5(x1?x2)2?4x1x2?516?4?215
?x2?y2?4254.?1,? ?,x?(kx?1)2?4,(1?k2)x?2kx?5?0
2?y?kx?1 当1?k?0,k??1时,显然符合条件;
2当1?k?0时,则??20?16k?0,k??225 25.
3522 直线AB为2x?y?4?0,设抛物线y?8x上的点P(t,t) 5 d?
2t?t2?45t2?2t?4(t?1)2?3335 ????5555 31
三、解答题
1.解:当??0时,cos0?1,曲线x2?y2?1为一个单位圆;
00y2x2??1为焦点在y轴上的椭圆; 当0???90时,0?cos??1,曲线11cos?00当??90时,cos90?0,曲线x?1为两条平行的垂直于x轴的直线;
002x2y2??1为焦点在x轴上的双曲线; 当90???180时,?1?cos??0,曲线
1?1cos?00当??180时,cos180??1,曲线x2?y2?1为焦点在x轴上的等轴双曲线。
00x2y2??1的a?3,c?5,不妨设PF1?PF2,则PF1?PF2?2a?6 2.解:双曲线
916F1F22?PF12?PF22?2PF1?PF2cos600,而F1F2?2c?10
222得PF1?PF2?PF1?PF2?(PF1?PF2)?PF1?PF2?100
PF1?PF2?64,S?1PF1?PF2sin600?163 2x1?x2y1?y2y?y,),得kAB?21, 22x2?x13.证明:设A(x1,y1),B(x2,y2),则中点M(b2x12?a2y12?a2b2,b2x22?a2y22?a2b2,得b2(x22?x12)?a2(y22?y12)?0,
x2?x1y22?y12b2AB即2,的垂直平分线的斜率k??, ??22y2?y1x2?x1aAB的垂直平分线方程为y?y1?y2x?xx?x??21(x?12), 2y2?y12y22?y12?x22?x12b2x2?x1当y?0时,x0? ?(1?2)2(x2?x1)a2a2?b2a2?b2?x0?. 而?2a?x2?x1?2a,??aa
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4.解:设A(x1,y1),B(x2,y2),AB的中点M(x0,y0),kAB?y2?y11??,
x2?x14而3x12?4y12?12,3x22?4y22?12,相减得3(x22?x12)?4(y22?y12)?0, 即y1?y2?3(x1?x2),?y0?3x0,3x0?4x0?m,x0??m,y0??3m
m29m22323??1,即?而M(x0,y0)在椭圆内部,则。 ?m?431313新课程高中数学训练题组参考答案
(数学选修1-1)第一章 导数及其应用 [基础训练A组]
一、选择题
f(x0?h)?f(x0?h)f(x0?h)?f(x0?h)?lim2[]
h?0h?0h2hf(x0?h)?f(x0?h)?2f'(x0) ?2limh?02h1.B lim2.C s'(t)?2t?1,s'(3)?2?3?1?5 3.C y'=3x2+1>0对于任何实数都恒成立 4.D f(x)?3ax?6x,f(?1)?3a?6?4,a?'2'10 33'2'5.D 对于f(x)?x,f(x)?3x,f(0)?0,不能推出f(x)在x?0取极值,反之成立
'3'3''6.D y?4x?4,令y?0,4x?4?0,x?1,当x?1时,y?0;当x?1时,y?0 得y极小值?y|x?1?0而端点的函数值y|x??2?27,y|x?3?72,得ymin?0 ,二、填空题
1.?1 f'(x0)?3x02?3,x0??1 2.
33?an???1,?? ? y'?3x2?4,k?y'x?|1??1,t44xcosx?sinx(sinx)'x?sinx?(x)'xcosx?sinx'?3. y?
x2x2x21111,k?y'|x?e?,y?1?(x?e),y?x xeee55'25.(??,?),(1,??) 令y?3x?2x?5?0,得x??,或x?1
334.,x?ey?0 y?'1e
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三、解答题
1.解:设切点为P(a,b),函数y?x3?3x2?5的导数为y'?3x2?6x
切线的斜率k?y'|x?a?3a2?6a??3,得a??1,代入到y?x3?3x2?5 得b??3,即P(?1,?3),y?3??3(x?1),3x?y?6?0。
2.解:y'?(x?a)'(x?b)(x?c)?(x?a)(x?b)'(x?c)?(x?a)(x?b)(x?c)' ?(x?b)(x?c)?(x?a)(x?c)?(x?a)(x ?b3.解:f?(x)?5x4?20x3?15x2?5x2(x?3)(x?1),
当f?(x)?0得x?0,或x??1,或x??3, ∵0?[?1,4],?1?[?1,4],?3?[?1,4] 列表:
x f'(x) f(x) ?1 (?1,0) + ↗ 0 0 1 (0,4) + ↗ 0 0
又f(0)?0,f(?1)?0;右端点处f(4)?2625;
∴函数y?x?5x?5x?1在区间[?1,4]上的最大值为2625,最小值为0。 4.解:(1)y?3ax?2bx,当x?1时,y'|x?1?3a?2b?0,y|x?1?a?b?3,
即?'2543?3a?2b?0,a??6,b?9
a?b?3?32'2'(2)y??6x?9x,y??18x?18x,令y?0,得x?0,或x?1
?y极小值?y|x?0?0
(数学选修1-1)第一章 导数及其应用 [综合训练B组]
一、选择题
1.C y?3x?6x?9?0,x??1,得x?3,当x??1时,y?0;当x??1时,y?0 当x??1时,y极大值?5;x取不到3,无极小值
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'2''2.D limh?0f(x0?h)?f(x0?3h)f(x0?h)?f(x0?3h)?4lim?4f'(x0)??12
h?0h4h'2'23.C 设切点为P,f(x)?3x?1,k?f(a)?3a?1?4,a??1, (a,b)0把a??1,代入到f(x)=x3+x-2得b??4;把a?1,代入到f(x)=x3+x-2得
b?0,所以P0(1,0)和(?1,?4)
4.B f(x),g(x)的常数项可以任意
18x3?112?0,(2x?1)(4x?2x?1)?0,x?5.C 令y?8x?2? 2xx2'(lnx)'x?lnx?x'1?lnx??0,x?e,当x?e时,y'?0;当x?e时,6.A 令y?22xx'11y'?0,y极大值?f(e)?,在定义域内只有一个极值,所以ymax?
ee二、填空题
?3 y'?1?2sixn?0x,?,比较0,,处的函数值,得ymax??3 6662633'2'?)7f,?(1)y1?0,?1x0?7(y时?1),x? 0?,2.? f(x)?3x?4,f(177222'23.(0,) (??,0),(,??) y??3x?2x?0,x?0,或x?
3331.
4.a?0,且b?3ac f(x)?3ax?2bx?c?0恒成立,
则?'22'2??????a?02???4b?12ac?0',a?0,且b2?3ac
0,f(1)?2a?a?b? ?1105.4,?11 f(x)?3x?2ax?b,f(1)?2a?b?3??2a?b??3?a??3?a?4 ?2,当a??3时,x?1不是极值点 ,?,或?b?3b??11??a?a?b?9?三、解答题
1.解:y?2x,k1?y|x?x0?2x0;y?3x,k2?y|x?x0?3x0 k1k2??1,6x303'''2'2??1,x?0?36。 62.解:设小正方形的边长为x厘米,则盒子底面长为8?2x,宽为5?2x V?(8?2x)(5?2x)x?4x?26x?40x
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