必修四综合检测
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学分综合测试题本试卷分第Ⅰ卷(选择题)和第Ⅱ卷(非选择题)两部分。
满分100分,考试时间90分钟。
第Ⅰ卷(选择题,共50分)一、单项选择题(本大题共25小题,每小题2分,共50分)1.2011年7月5日,广东省哲学社会科学“十二五”规划2011年度项目申报工作正式启动,这对促进该省哲学社会科学繁荣发展,更好地为经济社会发展服务发挥着重要引导和示范作用。
该省重视哲学社会科学繁荣发展的做法说明()A.哲学是人们对整个世界的正确看法 B.哲学是人们认识世界和改造世界的重要工具C.哲学是人类社会发展的原动力D.哲学的发展水平是社会文明程度的最主要标志2.相关数据表明,目前我国约有上亿的信教群众,30多万宗教教职人员,3000多个宗教团体,10多万处宗教活动场所。
尽管我国贯彻宗教信仰自由政策,但并不鼓励人们信仰宗教,这是因为,宗教教义从本质上讲是()A.古代朴素唯物主义世界观B.近代形而上学唯物主义世界观C.主观唯心主义世界观D.客观唯心主义世界观3.近年来的遥感探测工作发现,组成月球的物质和地球基本相同。
这有力地证明了()A.物质世界是永恒不变的B.不同的事物由相同的物质构成C.自然界按照自身的规律运动变化D.世界的真正统一性在于它的物质性4.2012年“中央一号文件”在总体思路上提出“三强三保”,在政策设计上明确“三大指向”,即围绕强科技保发展、强生产保供给、强民生保稳定,进一步加大强农惠农富农政策力度,奋力夺取农业好收成,合力促进农民较快增收,努力维护农村社会和谐稳定。
这体现了()①具体事物间联系的绝对性②任何两事物间都存在着对立统一关系③政府坚持群众观点和群众路线④政府维护群众利益的价值取向A.①②B.①③C.②③D.③④5.近年来,我国高度重视“地沟油”等食品安全问题,但要彻底解决“地沟油”问题,必须在源头“管控”的同时大力疏导,即创造合法产业链,利用市场机制处理餐厨废油,用其提炼燃料,让“地沟油”变废为宝。
第三章三角恒等变换综合检测题本试卷分第I 卷选择题和第U 卷非选择题两部分,满分150分,时间120 分钟。
第I 卷(选择题共60分)一、选择题(本大题共12个小题,每小题 5分,共60分,在每小题给出的四个选项中 只有一个是符合题目要求的 )n 3 41 .已知 0v av 2v 3<n 又 sin a= 5, cos (a+ ®= — 5,贝V sin ()B . 0 或 2424 C.25 24 D . ±25 [答案]Cn 3 4[解析]•/ 0v av 2 v 3v n 且 sin a= 5, COS ( a+ 3 = — 54 n3 3• cos a= 5 , 2< a+ 3v ㊁ n, • sin( a+ 3 = ±5,=sin( a+ 3cos a — cos( a+ 3)sin a才< 3v n ••• sin 3> 0•故排除 A , B , D.4 3 4⑵由 cos( a+ 3)= — 5及 Sin a= 3可得 sin 3= §(1 + cos 3)代入 sin 2 3+ cos 2 3= 1 中可解得 cos37 n=—1或一25,再结合2<仟n 可求sin 32.若sin Bv 0, cos2 0v 0,则在(0,2 内)B 的取值范围是()3 n3=0.sin3=- 5x 4-又氏才,n j, • sin 3> 0,故 sin 3= 24当 sin( a+ 3 =,sin 3= sin [( a+ a[点评](1)可用排除法求解,T=器53 245 = 25;A . n< 0< 25 nB.5T <e< ¥3 nC.y <e< 2 nD.严< 0<孕4 4[答案]B[解析]2 2 2•/ cos2 e< 0, • 1 —2sin < 0,即sin e>2或sin < —"2,又已知sin < 0, •— 1 < sin e<—亠2,2由正弦曲线得满足条件的e取值为54n<e< ¥3. 函数y= sin2x+ cos2x的图象,可由函数y= sin2x —cos2x的图象()A .向左平移f个单位得到B .向右平移f个单位得到8c.向左平移n个单位得到4D .向右平移4个单位得到[答案]C[解析]y= sin2x+ cos2x= , 2sin(2x+J=2si n2(x +》_ n _ ny= sin2x—cos2x= 2sin(2x—4)= . 2sin2(x—§)n n n其中x+8=(x+ 4)—8n•••将y= sin2x—cos2x的图象向左平移:个单位可得y= sin2x+ cos2x的图象.44. 下列各式中,值为~2的是()A . 2sin 15 cos15 °2 2B. cos 15。
第二章综合能力检测一、选择题(本大题共12个小题,每小题5分,共60分) 1.下列命题中正确的是( ) A .若a ·b =0,则a =0或b =0 B .若a ·b =0,则a ∥bC .若a ∥b ,则a 在b 上的投影为|a |D .若a ⊥b ,则a ·b =(a ·b )2 答案:D解析:若a ∥b ,则a 在b 上的投影为|a |或-|a |,平行时分夹角为0°和180°两种情况;a ⊥b ⇒a ·b =0,(a ·b )2=0.2.已知AB →=a +5b ,BC →=-2a +8b ,CD →=3(a -b ),则( ) A .A 、B 、C 三点共线 B .A 、B 、D 三点共线 C .B 、C 、D 三点共线 D .A 、C 、D 三点共线答案:B解析:由题意,知AB →=BC →+CD →=BD →,所以A 、B 、D 三点共线. 3.在平行四边形ABCD 中,AC 为一条对角线.若AB →=(2,4),AC →=(1,3),则BD →=( )A .(-2,-4)B .(-3,-5)C .(3,5)D .(2,4)答案:B解析:在平行四边形ABCD 中, AC →=AB →+AD →,BD →=AD →-AB →,∴BD →=(AC →-AB →)-AB → =(1,3)-2(2,4)=(1,3)-(4,8)=(-3,-5).4.平面向量a 与b 的夹角为60°,a =(2,0),|b |=1,则|a +2b |=( )A. 3 B .2 3 C .4 D .12答案:B解析:a =(2,0),∴|a |=2. |a +2b |2=a 2+4a ·b +4b 2=4+4×2×1×cos60°+4×1=12, ∴|a +2b |=2 3.5.[2011·广东卷]若向量a 、b 、c 满足a ∥b 且a ⊥c ,则c ·(a +2b )=( )A. 4B. 3C. 2D. 0 答案:D解析:由a ∥b 且a ⊥c , 得b ⊥c ,所以a ·c =0,b ·c =0. 所以,c ·(a +2b )=a ·c +2b ·c =0.6.已知向量OB →=(2,0),OC →=(2,2),CA →=(-1,-3),则OA →和OB →的夹角为( )A.π4B.5π12C.π3D.π12答案:A解析:由题意,得OA →=OC →+CA →=(1,-1), 则|OA →|=2,|OB →|=2,OA →·OB →=2, ∴cos 〈OA →,OB →〉=OA →·OB →|OA →||OB →|=22.又0≤〈OA →,OB →〉≤π,∴〈OA →,OB →〉=π4.故选A.7.已知平面向量a 、b 、c 满足|a |=1,|b |=2,|c |=3,且a 、b 、c 两两所成的角相等,则|a +b +c |等于( )A. 3 B .6或 2 C .6 D .6或 3答案:D解析:由题意,得a 、b 、c 两两所成的角均为120°或0°,当夹角为120°时,a ·b =-1,b ·c =-3,a ·c =-32,则|a +b +c |2=|a |2+|b |2+|c |2+2(a ·b +b ·c +a ·c )=3;当夹角为0°时,|a +b +c |=|a |+|b |+|c |=6.故选D.8.已知命题:“若k 1a +k 2b =0,则k 1=k 2=0”是真命题,则下面对a 、b 的判断正确的是( )A .a 与b 一定共线B .a 与b 一定不共线C .a 与b 一定垂直D .a 与b 中至少有一个为0 答案:B解析:根据平行四边形法则及向量共线的条件可知,a 与b 一定不共线.9.在△ABC 中,M 是BC 的中点,AM =1,点P 在AM 上且满足AP =2PM ,则P A →·(PB →+PC →)等于( )A .-49 B .-43 C.43 D.49答案:A解析:由题意可知,P 是△ABC 的重心, ∴P A →+PB →+PC →=0, ∴P A →·(PB →+PC →)=-P A →2 =-(23MA →)2=-49.10.与向量a =(1,3)的夹角为30°的单位向量是( ) A .(12,32)或(1,3) B .(32,12) C .(0,1) D .(0,1)或(32,12) 答案:D解析:设单位向量为e =(x ,y ),则cos30°=x +3y 2=32,x 2+y 2=1,验证即得D.11.对向量a =(x 1,y 1),b =(x 2,y 2)定义一种新的运算“*”的意义为a *b =(x 1y 2,x 2y 1),仍是一个向量;则对任意的向量a ,b ,c 和任意实数λ,μ,下面命题中:①a *b =b *a②(a *b )*b =a *(b *b ) ③(λa )*(μb )=(λμ)(a *b ) ④(a +b )*c =a *c +b *c 其中正确命题的个数为( ) A .3 B .2 C .1 D .0答案:B解析:可结合向量的运算性质加以验证知③④正确.12.设过点P (x ,y )的直线分别与x 轴的正半轴和y 轴的正半轴交于A 、B 两点,点Q 与点P 关于y 轴对称,O 点为坐标原点,若BP →=2P A →,且OQ →·AB →=1,则P 点的轨迹方程是( )A .3x 2+32y 2=1(x >0,y >0)B .3x 2-32y 2=1(x >0,y >0)C.32x 2-3y 2=1(x >0,y >0) D.32x 2+3y 2=1(x >0,y >0) 答案:D解析:设P (x ,y ),则Q (-x ,y ).设A (x A,0),x A >0,B (0,y B ),y B >0,BP →=(x ,y -y B ),P A →=(x A -x ,-y ).∵BP →=2P A →,∴x =2(x A -x ),y -y B =-2y , ∴x A =32x ,y B =3y (x >0,y >0).又∵OQ →·AB →=1,(-x ,y )·(-x A ,y B )=1, ∴(-x ,y )·(-32x,3y )=1, 即32x 2+3y 2=1(x >0,y >0).二、填空题(本大题共4个小题,每小题5分,共20分) 13.已知向量a =(4,-3),b =(x,2),且a ∥b ,则x =________. 答案:-83解析:由题意,得4×2+3x =0,得x =-83.14.[2011·重庆卷]已知单位向量e 1,e 2的夹角为60°,则|2e 1-e 2|=________.答案: 3解析:|2e 1-e 2|=(2e 1-e 2)2=4e 21+e 22-4e 1e 2=4+1-4×1×1 cos 60° = 3.15.设向量OA →=(3,1),OB →=(-1,2),向量OC →⊥OB →,且向量BC →∥OA →,当OD →+OA →=OC →时,OD →的坐标是______.答案:(11,6)解析:设OD →=(x ,y ),则由OD →+OA →=OC →,可得OC →=(3+x ,y +1),所以BC →=OC →-OB →=(4+x ,y -1),因为OC →⊥OB →及BC →∥OA →,可得⎩⎪⎨⎪⎧(3+x )·(-1)+(y +1)·2=0(4+x )-3(y -1)=0, 解之得⎩⎪⎨⎪⎧x =11,y =6.16.已知向量a =(6,2),b =(-4,12),直线l 过点A (3,-1),且与向量a +2b 垂直,则直线l 的方程为____.答案:2x -3y -9=0解析:设B (x ,y )为直线l 上的任意一点,则l 的方向向量为AB →=(x -3,y +1).又a +2b =(-2,3),直线l 与向量a +2b 垂直,所以(x -3,y +1)·(-2,3)=0,展开化简得2x -3y -9=0.三、解答题(本大题共6个小题,共70分,解答应写出必要的文字说明、证明过程或演算步骤)17.(本小题满分10分)已知|a |=3,|b |=4,且(2a -b )·(a +2b )≤4,求a 与b 的夹角θ的范围.解:由条件(2a -b )·(a +2b )≤4,可以得含cos θ的不等关系式. ∵(2a -b )·(a +2b )≤4,即2×32-2×42+3a·b ≤4, ∴a ·b ≤6,即|a ||b |cos θ=3×4cos θ≤6. ∴-1≤cos θ≤12,∴π3≤θ≤π.18.(本小题满分12分)等腰△ABC 中,BD 和CE 是两腰上的中线,且BD ⊥CE ,求顶角A 的余弦值.解:建立如图所示的直角坐标系,设A (0,a ),C (c,0),则B (-c,0),OA →=(0,a ),BA →=(c ,a ),OC →=(c,0),BC →=(2c,0).因为BD 和CE 分别为AC ,AB 的中线,所以BD →=12(BC →+BA →)=(3c 2,a2),同理CE →=(-3c 2,a 2),又BD →⊥CE →,故BD →·CE →=0,即-94c 2+a 24=0,故a 2=9c 2.所以cos ∠BAC =AB →·AC →|AB →||AC →|=a 2-c 2a 2+c 2=9c 2-c 29c 2+c 2=45.19.(本小题满分12分)已知|a |=3,|b |=2,a 与b 的夹角为60°,c =3a +5b ,d =m a -b ,c ⊥d ,求m 的值及a 与c 夹角的余弦值.解:由c =3a +5b ,d =m a -b ,可得c ·d =(3a +5b )·(m a -b )=3m a 2-3a ·b +5m a ·b -5b 2.因为|a |=3,|b |=2,a 与b 的夹角为60°,所以a ·b =|a |·|b |·cos60°=3×2×cos60°=3,所以c ·d =27m -3×3+15m -20=0,即42m =29,所以m =2942.因为a ·c =a ·(3a +5b )=3a 2+5a ·b =3×9+5×3=42.|a |=|3a +5b |=(3a +5b )2=9a 2+30a ·b +b 2×25=9×9+30×3+4×25=271,设a 与c 的夹角为θ,则cos θ=a ·c |a |·|c |=423×271=14271271. 20.(本小题满分12分)(1)已知|a |=4,|b |=3,(2a -3b )·(2a +b )=61,求a 与b 的夹角;(2)设OA →=(2,5),OB →=(3,1),OC →=(6,3),在OC →上是否存在点M ,使MA →⊥MB →,若存在,求出点M 的坐标,若不存在,请说明理由.解:(1)∵(2a -3b )·(2a +b )=61, ∴4a 2-4a ·b -3b 2=61. 又|a |=4,|b |=3,∴a ·b =-6. ∴cos θ=a ·b |a ||b |=-12,∴θ=120°.(2)设存在点M ,且OM →=λOC →=(6λ,3λ)(0<λ≤1),∴MA →=(2-6λ,5-3λ),MB →=(3-6λ,1-3λ).∴(2-6λ)(3-6λ)+(5-3λ)(1-3λ)=0,∴45λ2-48λ+11=0,解得:λ=13或λ=1115,∴OM →=(2,1)或OM →=(225,115).∴存在M (2,1)或M (225,115)满足题意.21.(本小题满分12分)已知向量OA →=(1,5),OB →=(7,1),OM →=(1,2),P 是直线OM 上的一个动点,当P A →·PB →取最小值时,求OP →的坐标,并求出cos ∠APB 的值.解:设OP →=t ·OM →=(t,2t )(t ≠0),所以P A →=OA →-OP →=(1-t,5-2t ),PB →=OB →-OP →=(7-t,1-2t ),所以P A →·PB →=(1-t,5-2t )·(7-t,1-2t )=(1-t )·(7-t )+(5-2t )·(1-2t )=5t 2-20t +12.令f (t )=5t 2-20t +12,则f (t )=5(t -2)2-8,所以当t =2时,f (t )的最小值为-8,此时OP →=(2,4),P A →·PB →=-8,|P A →|=2,|PB →|=34, 所以cos ∠APB =P A →·PB →|P A →|·|PB →|=-82·34=-41717.22.(本小题满分12分)用两条同样长的绳子拉一物体,物体受到的重力为G ,两绳受到的拉力分别为F 1,F 2,夹角为θ,如图.(1)求其中一根绳受的拉力|F 1|与|G |的关系式,用数学观点分析|F 1|的大小与夹角θ的关系;(2)求|F 1|的最小值;(3)如果每根绳的最大承受拉力为|G |,求θ的取值范围. 解:(1)由力的平衡得F 1+F 2+G =0, 设F 1,F 2的合力为F ,则F =-G , ∴F 1+F 2=F 且|F 1|=|F 2|,|F |=|G |,解直角三角形得cos θ2=12|F ||F 1|=|G |2|F 1|, ∴|F 1|=|G |2cos θ2,θ∈[0°,180°]. 由于函数y =cos x 在x ∈[0°,180°]上为减函数,∴θ逐渐增大时,cos θ2逐渐减小,|G |2cos θ2逐渐增大,∴θ增大时,|F 1|也增大.(2)由上述可知,当θ=0°时,|F 1|有最小值为|G |2.(3)依题意,|G |2≤|F 1|<|G |,∴12≤12cos θ2<1,即12<cos θ2≤1.∵y =cos x 在[0°,180°]上为减函数,∴0°≤θ2<60°,∴θ∈[0°,120°).。
(时间:150分钟;满分:150分)第Ⅰ卷(共36分)一、(15分,每小题3分)1.下列加点的词语注音全部正确的一组是()A.阜.盛(pù)角.色(jué) 簇.拥(cù)联袂.(mèi)B.竹箸.(zhù) 亲昵.(nì) 拂.尘(fú) 存殁.(mò)C.漱.盂(sòu ) 枭.雄(xiāo) 杜撰.(zhuàn) 栈.道(zhàn)D.牲醴.(lǐ) 喘.息(chuǎn) 暖.昧(ài) 诊.断(zhēn)解析:选B。
A项,“阜”读“fù”。
C项,“漱”读“shù”。
D项,“诊”读“zhěn”。
2.下列各组词语中没有错别字的一组是()A.精粹精络精疲力竭精诚所至,金石为开B.赠予授予予人口实同甘共苦,祸福予共C.即将立即若即若离一言即出,驷马难追D.挥毫毫发毫无二致失之毫厘,谬以千里解析:选D。
A项,精络—经络。
B项,祸福予共—祸福与共。
C项,一言即出—一言既出。
3.依次填入下面横线处的词语,最恰当的一组是()方永刚既是“知者”,________是一个“行者”。
他通过脚踏实地地________党的创新理论,使得党的创新理论的威力通过传播者知行统一的人格魅力更好地________出来。
A.也躬身体现 B.更躬行发挥C.更躬身体现D.也躬行发挥解析:选B。
第一个横线处应是递进关系。
躬行:是亲自去实行,符合语境。
“发挥”跟句中“威力”一词搭配恰当。
4.下列句子中,加点的成语使用正确的一项是()A.这位明星曾带给观众很多快乐,不少“粉丝”竞相模仿他的表演,但这次他因醉酒驾车而触犯法律的行为却不足为训....。
B.下午,今年的第一场春雨不期而遇....,虽然没有电视台预报的降水量大,但还是让京城一直干燥的空气变得湿润了一些。
C.伴着落日的余晖,诗人缓步登上了江边的这座历史名楼,极目远眺,晚霞尽染,鸿雁南飞,江河日下....,诗意油然而生。
单元综合检测(三)Ⅰ.阅读理解(共15小题;每小题2分,满分30分)ABotswana is situated in Southern Africa.There are many topquality places to enjoy your African trip.The Okavango DeltaThe Okavango Delta is the world's largest inland delta and is a top spot to visit during your Botswana trip.The whole delta covers an area of 15,000 km2.The Okavango River ends in this area flooding the whole region.Besides the regular flooding,rainfall can drastically increase the size of this water body,up to 22,000 km2.The delta also contains the Moremi Game Reserve (禁猎区)and it is one of the best places to see wildlife.Animals such as hippopotamuses,crocodiles,buffalo,rhinoceroses,elephants and antelopes can be very easily found in the region.There are over 500 species of birds in this area.The Chobe National ParkThe Chobe National Park is situated in Northwest Botswana.It is the third largest park in Botswana and is famous for its large wildlife population.The Chobe National Park has diverse animal habitats and it is wonderful to watch these beautiful animals right in front of you.The park is also very famous for its elephants and is considered to be the largest area for elephants in Africa.Apart from the huge elephant population,other wild animals such as lions,leopards,wild dogs,antelopes,hippopotamuses,buffalo and crocodiles can also be seen.The Kalahari Game ReserveThe Central Kalahari Game Reserve is situated in the Kalahari Desert,covering an area of 52,800 km2.It is the second largest game reserve in the rge areas of trees,bushes and grass are widely spread in this reserve,thus adding to the beauty of the place.The reserve contains a huge concentration of wildlife.Many wild animals including giraffes can be spotted easily there.【语篇解读】 本文介绍了Botswana三个值得一去的地方。
本册综合能力检测一、选择题(本大题共12个小题,每小题5分,共60分) 1.在△ABC 中,sin A ·cos A =-18,则cos A -sin A 的值为( ) A .-32 B .±32 C.52 D .-52答案:D解析:由(cos A -sin A )2=1-2sin A cos A =54,而在△ABC 中,因为sin A cos A <0可知sin A >0,cos A <0,∴cos A -sin A =-52.2.若|a |=1,|b |=2,|a +b |=7,则a 与b 的夹角θ的余弦值( ) A .-12 B.12 C.13 D .-13 答案:B解析:由|a +b |=7,得:7=(a +b )2=a 2+b 2+2a ·b =1+4+2×1×2cos θ, 所以cos θ=12.3.如图,在△ABC 中,BD →=12DC →,AE →=3ED →,若AB →=a ,AC →=b ,则BE →等于( )A.13a +13b B .-12a +14b C.12a +14b D .-13a +13b答案:B解析:BE →=AE →-AB →=34AD →-a =34(AB →+BD →)-a =34a -a +34BD →=-14a +34×13BC →=-14a +14(AC →-AB →)=-14a +14b -14a =14b -12a .4.函数y =log 15sin(π3-π4x )的单调递增区间是( ) A .[-23,103) B .[-23,103) C .[-23,103]D .[8k -23,8k +43)(k ∈Z ) 答案:D解析:将原函数转化为y =log 15[-sin(π4x -π3)],由复合函数的单调性可知,整个函数的单调递增区间就是y =sin(π4x -π3)的递增区间,且sin(π4x -π3)<0.5. 已知函数y =sin x 的定义域为[a ,b ],值域为[-1,12],则b -a 的值不可能是( )A.π3B.2π3 C .π D.4π3答案:A解析:画出函数y =sin x 的草图分析知b -a 的取值范围为[2π3,4π3],故选A.6.化简式子2-sin 22+cos4的值是( ) A .sin2 B .-cos2 C.3cos2 D .-3cos2 答案:D解析:将cos4运用倍角公式变形为1-2sin 22,从而原式化为3-3sin 22,再开方即得结果.7.已知三点A (1,1)、B (-1,0)、C (0,1),若AB →和CD →是相反向量,则点D 的坐标是( )A .(-2,0)B .(2,2)C .(2,0)D .(-2,-2) 答案:B解析:设出D 点的坐标(x ,y ),写出向量AB →和CD →的坐标形式,根据它们是相反向量,可以列出关于x ,y 的方程组,从而得解.8.函数y =A sin(ωx +φ)(A >0,ω>0)的部分图像如下图所示,则f (1)+f (2)+f (3)+…+f (11)的值等于( )A .2B .2+ 2C .2+2 2D .-2-2 2答案:C解析:由图像可知,f (x )=2sin π4x ,其周期为8, ∴f (1)+f (2)+f (3)+…+f (11) =f (1)+f (2)+f (3)=2sin π4+2sin π2+2sin 3π4=2+2 2.9.将函数y =sin2x 的图像向左平移π4个单位,再向上平移1个单位,所得图像的函数解析式是( )A .y =2cos 2xB .y =2sin 2xC .y =1+sin(2x +π4) D .y =cos2x 答案:A解析:平移后所得的解析式为:y =sin2(x +π4)+1 =1+cos2x =2cos 2x .10.a =(cos2α,sin α),b =(1,2sin α-1),α∈(π2,π),若a ·b =25,则tan(α+π4)等于( )A.13B.27C.17D.23答案:C解析:由题意得cos2α+sin α(2sin α-1)=25,整理得sin α=35.又α∈(π2,π),所以cos α=-45,所以tan α=-34.所以tan(α+π4)=tan α+tan π41-tan αtan π4=17.11.如右图,向量OA →=a ,OB →=b ,且BC →⊥OA →,C 为垂足,设向量OC →=λa (λ>0),则λ的值为( )A.a ·b|a |2 B.a ·b |a ||b |C.a ·b |b |D.|a ||b |a ·b答案:A解析:OC →为OB →在OA →上的射影.故|OC →|=a ·b|a |,∴OC →=a ·b |a |·a |a |=a ·b |a |2·a .12.使f (x )=sin(2x +θ)+3cos(2x +θ)为奇函数,且在[0,π4]上是减函数的θ的一个值是( )A .-π3 B.π3 C.2π3 D.4π3答案:C解析:f (x )=sin(2x +θ)+3cos(2x +θ)=2sin(2x +θ+π3),因为f (x )是奇函数,验证得B 、D 不成立;当θ=-π3时,f (x )=2sin2x ,当x ∈[0,π4]时,f (x )是增函数,A 不成立;当θ=2π3时,f (x )=2sin(2x +π)=-2sin2x 满足条件,故选C.二、填空题(本大共4个小题,每小题5分,共20分)13.已知向量OA →=(0,1),OB →=(k ,k ),OC →=(1,3),且AB →∥AC →,则实数k =________.答案:-1解析:∵AB →=(k ,k -1),AC →=(1,2),AB →∥AC →, ∴2k -(k -1)=0,∴k =-1.14.[2011·江苏卷]已知tan(x +π4)=2,则tan xtan2x 的值为________. 答案:49解析:由tan(x +π4)=tan x +11-tan x =2,得tan x =13,tan xtan2x =tan x ·1-tan 2x 2tan x =1-tan 2x 2=49.15.函数f (x )=cos xcos x 2-sin x 2的值域是__________.答案:(-2,2) 解析:f (x )=cos 2x2-sin 2x2cos x 2-sin x 2=cos x 2+sin x 2, 且cos x 2-sin x2≠0, 即sin x 2≠cos x 2,tan x2≠1,∴f (x )=2sin ⎝ ⎛⎭⎪⎫x 2+π4,x ≠2k π+π2,k ∈Z . ∵x 2≠k π+π4,x 2+π4≠k π+π2,∴sin ⎝ ⎛⎭⎪⎫x 2+π4≠±1,∴f (x )≠±2.∴f (x )∈(-2,2).16.已知y =sin x +cos x ,给出以下四个命题:①若x ∈[0,π],则y ∈[1,2];②直线x =π4是函数y =sin x +cos x 图像的一条对称轴;③在区间[π4,5π4]上函数y =sin x +cos x 是增函数;④函数y =sin x +cos x 的图像可由y =2cos x 的图像向右平移π4个单位长度而得到.其中正确命题的序号为________.答案:②④解析:将函数变形后逐个判断正确与否. y =sin x +cos x =2sin(x +π4).①若x ∈[0,π],则x +π4∈[π4,5π4],得sin(x +π4)∈[-22,1],即y ∈[-1,2],①不正确;②记f (x )=2sin(x +π4),∵f (π2-x )=2sin(π2-x +π4)=2sin(3π4-x )=2sin[π-(x +π4)]=2sin(x +π4)=f (x ).从而直线x =π4是函数y =sin x +cos x 图像的一条对称轴,②是正确的;③由于函数y =2sin(x +π4)是由y =2sin x 向左平移π4个单位长度得到的,而函数y =2sin x 在区间[π2,3π2]上是单调递减的,从而函数y =2sin(x +π4)在区间[π4,5π4]上也应该是单调递减的,即命题③不正确;④函数y =2cos x 的图像向右平移π4个单位长度得到函数y =2cos(x -π4)=2·cos(π4-x )=2cos[π2-(x +π4)]=2sin(x +π4),即函数y =sin x +cos x ,从而命题④正确.三、解答题(本大题共6个小题,共70分,解答应写出必要文字说明、证明过程或演算步骤)17.(本小题满分10分)已知点A (-3,-4)、B (5,-12). (1)求AB →的坐标及|AB →|;(2)若OC →=OA →+OB →,OD →=OA →-OB →,求OC →及OD →的坐标; (3)求OA →·OB →.解:(1)AB →=OB →-OA →=(8,-8), |AB →|=82+(-8)2=8 2.(2)OC →=(-3,-4)+(5,-12)=(2,-16), OD →=OA →+BO →=(-3,-4)+(-5,12)=(-8,8). (3)OA →·OB →=-3×5+(-4)×(-12)=33.18.(本小题满分12分)设函数f (x )=a ·(b +c ),其中向量a =(sin x ,-cos x ),b =(sin x ,-3cos x ),c =(-cos x ,sin x ),x ∈R .(1)求函数f (x )的最大值和最小正周期;(2)将函数y =f (x )的图像按向量d 平移,使平移后得到的图像关于坐标原点成中心对称,求长度最小的d .解:利用数量积的坐标运算将f (x )化简为一种角的三角函数形式后,再利用三角函数性质求解.(1)由题意得f (x )=a ·(b +c )=(sin x ,-cos x )·(sin x -cos x ,sin x -3cos x )=sin 2x -2sin x cos x +3cos 2x =2+cos2x -sin2x =2+2sin(2x +34π).故f (x )的最大值为2+2,最小正周期是2π2=π. (2)由sin(2x +34π)=0得2x +3π4=k π. 即x =k π2-3π8,k ∈Z . 于是d =(3π8-k π2,-2),|d |=(k π2-3π8)2+4(k ∈Z ).因为k 为整数,要使|d |最小,则只要k =1,此时d =(-π8,-2)即为所求.19.(本小题满分12分)[2011·广东卷]已知函数f (x )=2sin(13x -π6),x ∈R .(1)求f (5π4)的值;(2)设α、β∈[0,π2],f (3α+π2)=1013,f (3β+2π)=65,求cos(α+β)的值.解:(1)f (5π4)=2sin(13×5π4-π6) =2sin π4= 2.(2)∵α、β∈[0,π2],f (3α+π2)=1013,f (3β+2π)=65. ∴2sin α=1013,2sin(β+π2)=65, 即sin α=513,cos β=35. ∵cos α=1213,sin β=45.cos(α+β)=cos α·cos β-sin α·sin β=1213×35-513×45=1665.20.(本小题满分12分)已知函数f (x )=12sin2x sin φ+cos 2x cos φ-12sin(π2+φ)(0<φ<π),其图像过点(π6,12).(1)求φ的值;(2)将函数y =f (x )的图像上各点的横坐标缩短到原来的12,纵坐标不变,得到函数y =g (x )的图像,求函数g (x )在[0,π4]上的最大值和最小值.解:(1)因为f (x )=12sin2x sin φ+cos 2x cos φ-12sin(π2+φ)(0<φ<π).所以f (x )=12sin2x sin φ+1+cos2x 2cos φ-12cos φ=12sin2x sin φ+12cos2x cos φ=12(sin2x sin φ+cos2x cos φ)=12cos(2x -φ).又函数图像过点(π6,12),所以12=12·cos(2×π6-φ),即cos(π3-φ)=1.又0<φ<π,所以φ=π3.(2)由(1)知f (x )=12cos(2x -π3),将函数y =f (x )的图像上各点的横坐标缩短到原来的12,纵坐标不变,得到函数y =g (x )的图像,可知g (x )=f (2x )=12cos(4x -π3).因为x ∈[0,π4],所以4x ∈[0,π],因此4x -π3∈[-π3,2π3],故-12≤cos(4x -π3)≤1.所以y =g (x )在[0,π4]上的最大值和最小值分别为12和-14.21. (本小题满分12分)[2011·四川卷]已知函数f (x )=sin(x +7π4)+cos(x -3π4),x ∈R .(1)求f (x )的最小正周期和最小值;(2)已知cos(β-α)=45,cos(β+α)=-45,0<α<β≤π2,求证:[f (β)]2-2=0.解:(1)∵f (x )=sin(x +7π4-2π)+sin(x -3π4+π2)=sin(x -π4)+sin(x -π4)=2sin(x -π4).∴T =2π,f (x )的最小值为-2.(2)由已知得cos β·cos α+sin βsin α=45,cos βcos α-sin βsin α=-45,两式相加得2cos βcos α=0,0<α<β≤π2,β=π2,∴[f (β)]2-2=4sin 2π4-2=0.22. (本小题满分12分)已知a =(cos 5x 3,sin 5x 3),b =(cos x 3,-sin x 3),x∈[0,π2].(1)求a ·b 及|a +b |;(2)若f (x )=a ·b -2λ|a +b |(其中λ>0)的最小值是-32,求λ的值. 解:(1)a ·b =cos 5x 3cos x 3-sin 5x 3·sin x 3=cos2x .|a +b |=a 2+2a ·b +b 2= (cos 25x 3+sin 25x 3)+2cos2x +(sin 2x 3+cos 2x3)=2+2cos2x =4cos 2x .又x ∈[0,π2],∴cos x >0,∴|a +b |=2cos x .(2)f (x )=a ·b -2λ|a +b |=cos2x -2λ·2cos x =2cos 2x -4λcos x -1 =2(cos x -λ)2-2λ2-1.①当0<λ≤1时,f (x )的最小值为-2λ2-1, ∴-2λ2-1=-32,∴λ=12.②当λ>1时,cos x =1时f (x )取最小值1-4λ, ∴1-4λ=-32,∴λ=58,又λ>1,故应舍去.所以,所求λ的值为1 2.。
第一章综合能力检测一、选择题(本大题共12个小题,每小题5分,共60分) 1.下列等式成立的是( ) A .sin π3=12 B .cos 5π6=-12 C .sin(-7π6)=12 D .tan 2π3= 3答案:C解析:sin π3=32,cos 5π6=-32,tan 2π3=-3, sin(-7π6)=12.2.函数y =45sin(2x +π3)的图像( ) A .关于原点对称 B .关于点(-π6,0)对称 C .关于y 轴对称 D .关于直线x =π6对称 答案:B3.如果sin(π+A )=-12,那么cos(32π-A )的值是( ) A .-12 B.12 C .-32 D.32答案:A解析:由sin(π+A )=-12,得sin A =12,则cos(32π-A )=-sin A =-12.4.函数y =sin(ωx +φ)(x ∈R ,ω>0,0≤φ<2π)的部分图像如图,则( )A .ω=π2,φ=π4 B .ω=π3,φ=π6 C .ω=π4,φ=π4 D .ω=π4,φ=5π4 答案:C解析:依图像可知,T 4=3-1=2,∴T =8,ω=2πT =π4.将点(1,1)代入y =sin(π4x +φ)中,得1=sin(π4+φ).∴π4+φ=π2,∴φ=π4.5.设0≤x ≤2π,使sin x ≥12且cos x <22同时成立的x 值是( ) A.π6≤x ≤5π6 B.π6≤x ≤74π C.5π6≤x ≤74π D.π4<x ≤56π答案:D解析:由正弦曲线得sin x ≥12时,x ∈[π6,56π];由余弦曲线得cos x <22时,x ∈(π4,74π),∴sin x ≥12且cos x <22时,x ∈(π4,56π].6.若函数y =sin(2x +θ)的图像向左平移π6个单位后恰好与y =sin2x 的图像重合,则θ的最小正值是( )A.4π3B.π3 C.5π6 D.5π3答案:D解析:将y =sin(2x +θ)的图像左移π6个单位得y =sin[2(x +π6)+θ]=sin(2x +π3+θ),故π3+θ=2k π,k ∈Z ,因此θ的最小正值为5π3.7. [2011·陕西卷]设函数f (x )(x ∈R )满足f (-x )=f (x ),f (x +2)=f (x ),则y =f (x )的图像可能是( )答案:B解析:由f (-x )=f (x )得,f (x )为偶函数,所以图像关于y 轴对称. 又f (x +2)=f (x )得f (x )的周期为2,故选B.8. 令a =sin(π-1),b =sin2,c =cos1,则它们的大小顺序是( ) A .a >b >c B .b >a >c C .c >b >a D .c >a >b 答案:B解析:c =sin(π2+1),且π>π2+1>π-1>2>π2,又y =sin x 在[π2,π]上是减函数,∴sin(π2+1)<sin(π-1)<sin2,即c <a <b .9.已知f (x )=cos2x -1,g (x )=f (x +m )+n ,则使g (x )为奇函数的实数m ,n 的可能取值为( )A .m =π2,n =-1 B .m =π2,n =1 C .m =-π4,n =-1 D .m =-π4,n =1答案:D解析:显然n =1, ∴g (x )=cos(2x +2m ).∵g (x )为奇函数,∴cos2m =0,∴2m =k π+π2. 经检验D 符合条件.10.已知f (x )=sin(2x +φ)的一个单调区间是[π3,5π6],则φ的一个值是( )A .-π6 B.π6 C .-π2 D.π2答案:A解析:排除法,若φ=±π2,f (x )=±cos2x 不合题意,若φ=π6,也不适合题意,故选A.11.下列命题正确的个数是( ) ①函数y =sin|x |不是周期函数;②函数y =tan x 在定义域内是增函数; ③函数y =|cos 2x +12|的周期是π2; ④函数y =sin(5π2+x )是偶函数. A .0 B .1 C .2 D .3答案:B解析:用排除法将错误说法淘汰.对于①,从其图像可以说明其不是周期函数;对于②,∵0<π,而tan0=tanπ,∴y =tan x 在定义域内不是增函数;对于③,y =|cos2(x +π2)+12|=|12-cos2x |≠|cos2x +12|,因此π2不是y =|cos2x +12|的周期;对于④,f (x )=sin(5π2+x )=sin(2π+π2+x )=cos x ,显然是偶函数.12. [2011·辽宁卷]已知函数f (x )=A tan(ωx +φ)(ω>0,|φ|<π2),y =f (x )的部分图像如图,则f (π24)=( )A. 2+ 3B. 3C. 33D. 2- 3答案:B解析:由图像可知:T 2=3π8-π8=π4,即T =π2. 所以ω=2.由图像知,图像过点(3π8,0), 所以0=A tan(2×3π8+φ), 即34π+φ=k π(k ∈Z ).所以φ=k π-3π4(k ∈Z ),又|φ|<π2, 所以φ=π4,再由图像过点(0,1), 所以A =1,则f (x )=tan(2x +π4), 故f (π24)=tan(2×π24+π4)=tan π3= 3.二、填空题(本大题共4个小题,每小题5分,共20分) 13.函数y =sin(π6-2x )的单调递减区间是________. 答案:[k π-π6,k π+π3],k ∈Z解析:∵y =sin(π6-2x )=-sin(2x -π6),∴令2k π-π2≤2x -π6≤2k π+π2,k ∈Z ,∴k π-π6≤x ≤k π+π3,k ∈Z .14.y =lg(cos x -sin x )的定义域是________. 答案:(2k π-34π,2kx +π4)(k ∈Z )解析:由cos x -sin x >0知,cos x >sin x ,由单位圆知2k π-34π<x <2k π+π4.15.如下图是函数y =A sin(ωx +φ)+k (|φ|<π2)在一个周期内的图像,那么这个函数的一个解析式是______.答案:y =3sin(2x +π3)-1解析:由图可知A =3,k =-1,ω=2,且当x =-π6时,sin(2x +φ)=0,又|φ|<π2,故φ=π3.16.已知函数f (x )=2sin ωx (ω>0)在区间[-π3,π4]上的最小值是-2,则ω的最小值是________.答案:32解析:函数f (x )=2sin ωx (ω>0)在区间[-π3,π4]上的最小值是-2,则ωx 的取值范围是[-ωπ3,ωπ4],∴-ωπ3≤-π2,或ωπ4≥3π2,∴ω≥32,即ω的最小值等于32.三、解答题(本大题共6个小题,共70分,解答应写出必要的文字说明、证明过程或演算步骤)17. (本小题满分10分)设tan(α+8π7)=a , 求sin (15π7+α)+3cos (α-13π7)sin (20π7-α)-cos (α+22π7)的值. 解:原式=sin (π+8π7+α)+3cos (α+8π7-3π)sin (4π-8π7-α)-cos (α+8π7+2π) =-sin (8π7+α)-3cos (α+8π7)-sin (8π7+α)-cos (α+8π7) =tan (8π7+α)+3tan (8π7+α)+1=a +3a +1. 18. (本小题满分12分)[2011·浙江卷]已知函数f (x )=A sin(π3x +φ),x ∈R ,A >0,0<φ<π2,y =f (x )的部分图像如图所示,P 、Q 分别为该图像的最高点和最低点,点P 的坐标为(1,A ).求f (x )的最小正周期及φ的值. 解:(1)由题意得,T =2ππ3=6.因为P (1,A )在y =A sin(π3x +φ)的图像上, 所以sin(π3+φ)=1. 又因为0<φ<π2, 所以φ=π6.19.(本小题满分12分)函数f (x )=A sin(ωx +φ),x ∈R (其中A >0,ω>0,0<φ<π2)的图像与x 轴的交点中,相邻两个交点之间的距离为π2,且图像上一个最低点为M (2π3,-2).(1)求f (x )的解析式;(2)当x ∈[π12,π2]时,求f (x )的值域. 解:(1)由最低点为M (2π3,-2)得A =2.由x 轴上相邻两个交点之间的距离为π2得T 2=π2,即T =π, ∴ω=2πT =2ππ=2.由点M (2π3,-2)在图像上得2sin(2×2π3+φ)=-2, 即sin(4π3+φ)=-1, 故4π3+φ=2k π-π2,k ∈Z ,∴φ=2k π-116π. 又φ∈(0,π2),∴φ=π6,故f (x )=2sin(2x +π6). (2)∵x ∈[π12,π2],∴2x +π6∈[π3,7π6], 当2x +π6=π2,即x =π6时,f (x )取得最大值2; 当2x +π6=7π6,即x =π2时,f (x )取得最小值-1, 故f (x )的值域为[-1,2].20.(本小题满分12分)[2011·福建卷]已知等比数列{a n }的公比q =3,前3项和S 3=133.(1)求数列{a n }的通项公式;(2)若函数f (x )=A sin(2x +φ)(A >0,0<φ<π)在x =π6处取得最大值,且最大值为a 3,求f (x )的解析式.解:(1)由q =3,S 3=133得a 1(1-33)1-3=133,解得a 1=13.所以a n =13×3n -1=3n -2. (2)由(1)知a n =3n -2,所以a 3=3. 因为函数f (x )的最大值为3,所以A =3. 因为当x =π6时,f (x )取得最大值,所以sin(2×π6+φ)=1,又0<φ<π,故φ=π6.所以函数f (x )的解析式为f (x )=3sin(2x +π6).21.(本小题满分12分)已知函数f (x )=sin(ωx +φ)(ω>0,0≤φ≤π)为偶函数,且其图像上相邻的一个最高点和最低点之间的距离为4+π2.(1)求函数f (x )的表达式;(2)若sin α+f (α)=23,求2sin 2(3π-α)tan (3π+α)的值. 解:(1)∵f (x )为偶函数,∴sin(-ωx +φ)=sin(ωx +φ),即2sin ωx cos φ=0恒成立,∴cos φ=0,又0≤φ≤π,∴φ=π2.又其图像上相邻的一个最高点和最低点之间的距离为4+π2,设其最小正周期为T ,则T 2=4+π2-22=π.∴T =2π,∴ω=1,∴f (x )=cos x .(2)∵原式=2sin 2αtan α=2sin αcos α,又sin α+cos α=23,∴1+2sin αcos α=49,∴2sin αcos α=-59,即原式=-59.22.(本小题满分12分)设函数f (x )=2sin(2x +π4)+2.(1)用“五点法”作出函数f (x )在一个周期内的简图;(2)求函数f (x )的周期、最大值、最小值及当函数取最大值和最小值时相应的x 值的集合;(3)求函数f (x )的单调递增区间;(4)说明函数f (x )的图像可以由y =sin x (x ∈R )的图像经过怎样的变换而得到.解:(1)列表:函数图像如下图:(2)周期T =π,f (x )max =2+2,此时x ∈{x |x =k π+π8,k ∈Z }.f (x )min =2-2,此时x ∈{x |x =k π+58π,k ∈Z }.(3)函数f (x )的单调递增区间为:[k π-38π,k π+π8](k ∈Z ).(4)先将y =sin x (x ∈R )的图像向左平移π4个单位长度,然后将所得图像上各点的横坐标缩小为原来的12(纵坐标不变),再将所得图像上各点的纵坐标伸长为原来的2倍(横坐标不变),最后将所得图像向上平移2个单位长度,就可得到f(x)=2sin(2x+π4)+2的图像.。
人教A版高中数学必修四测试题及答案全套人教A版高中数学必修四测试题及答案全套阶段质量检测(一)一、选择题(本大题共12小题,每小题5分,共60分。
在每小题给出的四个选项中,只有一项是符合题目要求的。
)1.在0°~360°的范围内,与-510°终边相同的角是()A。
330° B。
210° C。
150° D。
30°2.若sinα = 3/3,π/2 < α < π,则sin(α+π/2) = ()A。
-6/3 B。
-1/2 C。
16/2 D。
33.已知弧度数为2的圆心角所对的弦长也是2,则这个圆心角所对的弧长是()A。
2 B。
2sin1 C。
2sin1 D。
sin24.函数f(x) = sin(x-π/4)的图象的一条对称轴是()A。
x = π/4 B。
x = π/2 C。
x = -π/4 D。
x = -π/25.化简1+2sin(π-2)·cos(π-2)得()A。
sin2+cos2 B。
cos2-sin2 C。
sin2-cos2 D。
±cos2-sin26.函数f(x) = tan(x+π/4)的单调增区间为()A。
(kπ-π/2.kπ+π/2),k∈Z B。
(kπ。
(k+1)π),k∈ZC。
(kπ-4π/4.kπ+4π/4),k∈Z D。
(kπ-3π/4.kπ+3π/4),k∈Z7.已知sin(π/4+α) = 1/√2,则sin(π/4-α)的值为()A。
1/3 B。
-1/3 C。
1/2 D。
-1/28.设α是第三象限的角,且|cosα| = α/2,则α的终边所在的象限是()A。
第一象限 B。
第二象限 C。
第三象限 D。
第四象限9.函数y = cos2x+sinx在[-π/6.π/6]的最大值与最小值之和为()A。
3/4 B。
2 C。
1/3 D。
4/310.将函数y = sin(x-π/3)的图象上所有点的横坐标伸长到原来的2倍(纵坐标不变),再将所得的图象向左平移一个单位,得到的图象对应的解析式为()A。
第三章综合能力检测一、选择题(本大题共12个小题,每小题5分,共60分) 1. cos 215°-sin 215°的值是( ) A.12 B .-12 C.32 D .-32答案:C解析:cos 215°-sin 215°=cos30°=32.2. [2011·福建卷]若α∈(0,π2),且sin 2α+cos2α=14,则tan α的值等于( )A. 22B. 33C. 2D. 3答案:D解析:sin 2α+cos2α=sin 2α+1-2sin 2α =1-sin 2α=14,所以,sin 2α=34,因为α∈(0,π2),所以,sin α=32,cos θ=12, 所以,tan α=sin αcos α= 3.3.若cos α=-45,α是第三象限的角,则1+tan α21-tan α2=( )A .-12 B.12 C .2 D .-2答案:A解析:∵cos α=-45且α是第三象限的角, ∴sin α=-35,1+tan a 21-tan α2=1+sin α2cos α21-sin α2cos α2=cos α2+sin α2cos α2-sin α2=⎝⎛⎭⎪⎫cos α2+sin α22⎝ ⎛⎭⎪⎫cos α2-sin α2⎝ ⎛⎭⎪⎫cos α2+sin α2 =1+sin αcos α=25-45=-12.故选A.4.函数y =cos 2(x -π4)-cos 2(x +π4)的值域为( ) A .[-1,0] B .[0,1] C .[-1,1] D .[-12,1]答案:C解析:可用降幂公式,∵y =1+cos (2x -π2)2-1+cos (2x +π2)2=12[cos(2x -π2)-cos(2x +π2)]=12(sin2x +sin2x )=sin2x ,∴-1≤y ≤1. 5.若sin(π6-α)=13,则cos(2π3+2α)的值为( ) A.13 B .-13 C.79 D .-79答案:D解析:∵(π6-α)+(π3+α)=π2, ∴cos(23π+2α)=2cos 2(π3+α)-1 =2sin 2(π6-α)-1=2×(13)2-1=-79.6.在△ABC 中,tan A +tan B +3=3tan A ·tan B 且sin A cos A =34,则此三角形是( )A .等腰三角形B .直角三角形C .等边三角形D .等腰直角三角形答案:C解析:∵12sin2A =34,∴sin2A =32,∴A =30°或60°.又tan A +tan B =-3(1-tan A ·tan B ),∴tan A +tan B 1-tan A tan B =-3,即tan(A +B )=-3,∴A +B =120°.若A =30°,则B =90°,tan B 无意义,∴A =60°,B =60°,∴△ABC 为等边三角形.7.函数y =cos2x cos π5-2sin x cos x sin 6π5的递增区间是( ) A .[k π+π10,k π+3π5](k ∈Z ) B .[k π-3π20,k π+7π20](k ∈Z ) C .[2k π+π10,2k π+3π5](k ∈Z ) D .[k π-2π5,k π+π10](k ∈Z ) 答案:D解析:y =cos2x cos π5+sin2x sin π5=cos(2x -π5) 由2k π-π≤2x -π5≤2k π,k ∈Z , ∴2k π-45π≤2x ≤2k π+π5,k ∈Z . ∴k π-2π5≤x ≤k π+π10,k ∈Z .8.E ,F 是等腰直角△ABC 斜边AB 上的三等分点,则tan ∠ECF =( )A.1627B.23C.33D.34答案:D 解析:如图,取AB 的中点D ,连结CD ,则∠ECF =2∠ECD ,设AB =2a ,则CD =AD =a ,ED =a 3,tan ∠ECD =DE CD =13,∴tan ∠ECF =tan2∠ECD =2×131-⎝ ⎛⎭⎪⎫132=34,故选D.9.已知向量m =(cos θ,sin θ)和n =(2-sin θ,cos θ),θ∈(π,2π),且|m +n |=825,则cos(θ2+π8)的值为( )A .-45 B.45 C .-35 D.35答案:A解析:m +n =(cos θ-sin θ+2,cos θ+sin θ), |m +n |=(cos θ-sin θ+2)2+(cos θ+sin θ)2 =4+22(cos θ-sin θ)=21+cos (θ+π4). 由|m +n |=825得cos(θ+π4)=725,又θ∈(π,2π),所以5π8<θ2+π8<9π8,所以cos(θ2+π8)<0,所以cos(θ2+π8)=-1+cos (θ+π4)2=-1+7252=-45.10.已知(sin x -2cos x )(3+2sin x +2cos x )=0,则sin2x +2cos 2x1+tan x 的值为( )A.85B.58C.25D.52答案:C解析:∵3+2sin x +2cos x =3+22sin(x +π4)>0,(sin x -2cos x )(3+2sin x +2cos x )=0,∴sin x -2cos x =0,∴tan x =2.∴原式=2cos x (sin x +cos x )1+sin x cos x=2cos 2x (sin x +cos x )cos x +sin x =2cos 2x =2cos 2x sin 2x +cos 2x=2tan 2x +1=25.11.若动直线x =a 与函数f (x )=sin x 和g (x )=cos x 的图像分别交于M 、N 两点,则|MN |的最大值为( )A .1 B. 2 C. 3 D .2答案:B解析:依题意得点M 、N 的坐标分别为(a ,sin a ),(a ,cos a ), ∴|MN |=|sin a -cos a | =|2(sin a ·22-cos a ·22)| =|2sin(a -π4)|≤2(a ∈R ),∴|MN |max = 2.12.定义行列式运算:⎪⎪⎪⎪⎪⎪a 1 a 2a 3 a 4=a 1a 4-a 2a 3,将函数 f (x )=⎪⎪⎪⎪⎪⎪3 cos x 1 sin x 的图像向左平移m 个单位(m >0),若所得图像对应的函数为偶函数,则m 的最小值是( )A.2π3B.π3 C.π8 D.56π答案:A解析:由题知f (x )=3sin x -cos x =2(32sin x -12cos x )=2sin(x -π6),其图像向左平移m 个单位后变为y =2sin(x -π6+m ),平移后其对称轴为x -π6+m =k π+π2,k ∈Z .若为偶函数,则x =0,所以m =k π+2π3,故m 的最小值为2π3.二、填空题(本大题共4个小题,每小题5分,共20分) 13.计算sin43°cos13°-cos43°sin13°的结果等于________. 答案:12解析:sin43°cos13°-cos43°sin13°=sin(43°-13°)=sin30°=12. 14.设向量a =(1,0),b =(cos θ,sin θ),其中0≤θ≤π,则 |a +b |的最大值是__________. 答案:2解析:|a +b |=(1+cos θ)2+sin 2θ=2+2cos θ.∵0≤θ≤π,∴-1≤cos θ≤1,|a +b |的最大值是2+2=2. 15.已知α为钝角,β为锐角,且sin α=45,sin β=1213,则 cos α-β2的值为__________. 答案:76565解析:由已知,得cos α=-35,cos β=513, cos(α-β)=cos αcos β+sin αsin β=3365. ∴2cos2α-β2-1=3365.∴cos α-β2=±76565.又∵0<α-β2<π2,∴cos α-β2=76565. 16.对于下列命题:①函数y =-sin(k π+x )(k ∈Z )为奇函数; ②函数y =cos 2x 的最小正周期是π;③函数y =sin(-2x +π3)的图像可由函数y =-sin2x 的图像向左平移π6个单位长度得到;④函数y =cos|x |是最小正周期为π的周期函数; ⑤函数y =sin 2x +cos x 的最小值是-1.其中真命题的编号是__________.(写出所有真命题的编号) 答案:①②⑤解析:①中,当k 是偶数时,y =-sin x 为奇函数;当k 是奇数时,y =sin x 为奇函数,所以①正确;②中,y =cos 2x =1+cos2x2,则周期为π,所以②正确; ③中,函数y =-sin2x 的图像向左平移π6个单位长度,得函数y =-sin(2x +π3)≠sin(-2x +π3),所以③不正确;④中,y =cos|x |=cos x ,则其周期是2π,所以④不正确; ⑤中,y =sin 2x +cos x =-cos 2x +cos x +1=-(cos x -12)2+54,当cos x =-1,函数取最小值-1,所以⑤正确.三、解答题(本大题共6个小题,共70分,解答应写出必要的文字说明,证明过程或演算步骤)17. (本小题满分10分)已知tan(α+π4)=-12(π2<α<π). (1)求tan α的值; (2)求sin2α-2cos 2αsin (α-π4)的值.解:(1)由tan(α+π4)=-12,得1+tan α1-tan α=-12.解之,得tan α=-3.(2)sin2α-2cos 2αsin (α-π4)=2sin αcos α-2cos 2α22(sin α-cos α)=22cos α. ∵π2<α<π且tan α=-3, ∴cos α=-1010.∴原式=-255.18.(本小题满分12分)求证:sin2x +11+cos2x +sin2x=12tan x +12.证明:左边=sin2x +12cos 2x +sin2x=2sin x cos x +sin 2x +cos 2x 2cos 2x +2sin x cos x=(sin x +cos x )22cos x (sin x +cos x )=sin x +cos x 2cos x =12tan x +12=右边. ∴原等式成立.19.(本小题满分12分)已知sin(α+3π4)=513,cos(π4-β)=35,且-π4<α<π4,π4<β<3π4,求cos(α-β)的值.解:∵-π4<α<π4,∴π2<α+3π4<π, ∴cos(α+3π4)=-1-sin 2(α+3π4)=-1213.∵π4<β<3π4,∴-π2<π4-β<0, ∴sin(π4-β)=-1-cos 2(π4-β)=-45.∴cos(α-β)=-cos[(α+3π4)+(π4-β)]=sin(α+3π4)sin(π4-β)-cos(α+3π4)cos(π4-β)=1665.20.(本小题满分12分)△ABC 的三个内角为A 、B 、C ,求当A 为何值时,cos A +2cos B +C2取得最大值?并求出这个最大值.解:利用A +B +C =π,把cos A +2cos B +C2化为同角三角函数式,再求最大值.由A +B +C =π,得B +C 2=π2-A 2,∴cos B +C 2=sin A 2,∴cos A +2cos B +C 2=cos A +2sin A 2=1-2sin 2A 2+2sin A 2=-2(sin A 2-12)2+32.当sin A 2=12,即A =π3时(∵A 是△ABC 的一个内角,∴A 2=5π6不合题意,舍去),cos A +2cos B +C 2取得最大值32.21.(本小题满分12分)已知函数f (x )=-23sin 2x +sin2x + 3.(1)求函数f (x )的最小正周期和最小值;(2)在给出的直角坐标系中(如下图),画出函数y =f (x )在区间[0,π]上的图像.解:(1)f (x )=3(1-2sin 2x )+sin2x=sin2x +3cos2x =2sin(2x +π3).所以f (x )的最小正周期T =2π2=π,最小值为-2.(2)列表:x,0,π12,π3,7π12,5π6,π2x +π3,π3,π2,π,3π2,2π,7π3f (x ),3,2,0,-2,0,3描点连线得图像,如下图所示.22.(本小题满分12分)[2011·天津卷]已知函数f (x )=tan(2x +π4).(1)求f (x )的定义域与最小正周期;(2)设x ∈(0,π4),若f (α2)=2cos2x ,求α的大小.解:(1)由2x +π4≠π2+k π,k ∈Z ,得x ≠π8+k π2,k ∈Z .所以f (x )的定义域为{x ∈R |x ≠π8+k π2,k ∈Z }.f (x )的最小正周期为π2.(2)由f (α2)=2cos2α,得tan(α+π4)=2cos2α,sin (α+π4)cos (α+π4)=2(cos 2α-sin 2α)整理得:sin α+cos αcos α-sin α=2(cos α+sin α)(cos α-sin α) 因为α∈(0,π4),所以sin α+cos α≠0,因此(cos α-sin α)2=12即sin2α=12,由α∈(0,π4),得2α∈(0,π2),所以2α=π6,即α=π12.。
英语周报高一必修四综合能力检测八【听力材料】:(Text 1)W: What’s new with you,Jack?M:Well,I met a really nice woman.We’ve been going out for three months and things look good now.(Text 2)M: When did you first find the door broken and things missing?W:After I got up,around 5:20.Then I called the police station.(Text 3)W: Pass me the flour,please.M:Which tin is it in?W:The one at the end of the shelf.It’s slightly smaller than the others.M:Oh,right.(Text 4)W:Do you know why George hasn’t come ye t?M:Yes.He was planning to come,but his wife’s father fell downsome stairs and they had to take him to a hospital.W:I’m sorry to hear that.(Text 5)W:Hi,Tony.How did your experiment go yesterday?M: Well,it wasn’t as easy as I had thought.I have to con tinue doing it tonight.(Text 6)M:Is that Ann?W:Yes.M:This is Mike.How are things with you?W:Oh,very well,but I’m very busy.M:Busy? But you’ve finished all your exams?W:Yes,but I have to help my little sister with her foreign language.M:How about coming out with me this evening?There’s a new film on.W:I’m afraid I can’t.A friend of mine is coming from the south and I have to go to the station to meet him.M:What a pity!How about the weekend then?W:No,I’ve arranged to go to an art exhi bition with my parents.M:What about next week sometime?W:Maybe.(Text 7)W:I hear there will be a football competition between all senior schools next month.Is that so?M:That’s true.W:Would you please go into some more details?M:Well,the competition will be held in our school and it will begin on August 11.The competition will last a whole week.W:Anything else?M:Yes,both the girls and boys competition will be held at the same time.The girls competition will be held in the morning and the boys competition will be held in the afternoon.W:Yes? Sounds exciting.M:We are both members of our school football team.We should be ready for it.W:Of course.It’s a long time since we had the last football competition last time.I’m really looking forward to anothercompetition.M:Me,too.(Text 8)W: Excuse me.I am from STM.We are carrying out a survey on the traffic in our city.Do you mind if I ask you some questions?M:No,not at all.Go ahead.W:Good,thanks.What do you do,sir?M:I am a teacher.I teach children French.W:Great.Do you live far from the school? I mean,how do you usually go to work?M:Well,mostly by car.But once in a while,I prefer to ride my bike.You know,I live quite far from the school,about 20 miles.And I have to spend about an hour riding to school.But it only takes me less than a quarter of an hour to drive my car,unless the traffic is very bad.W:I see.Does this happen often? I mean the bad traffic.M:Yes,sure! I often get stuck on the way,and the problem’s getting worse and worse.W:That’s all of my questions.Thank you very much.M:You are welcome.(Text 9)M: Customer service.Andney Grant speaking.How may I help you?W:I can’t believe this is happening.I called and ordered a 32?inch bag last Friday.But today I found that you sent me a 24?inch one.I was planning to use that bag during our vacation in Mexico,but it doesn’t seem possible any more because we will take off on Saturday.It’s only two days away.What am I supposed to do?M:I’m really sorry,madam. I’ll check right away.Would you please tell me your order number?W:It’s CE2938.M:Just a minute.I do apologize,madam.There did seem to be a mistake.I’ll have the corre ct size bag sent to you by overnight mail right away.It will arrive in time for your Saturday trip.Again I apologize for any inconvenience caused by our mistake.I promise it won’t happen again.W:OK.Well,thank you.M:Thank you,madam,for choosing Linch mail.I hope you willhave a wonderful vacation.(Text 10)I wasn’t too fond of the lecture classes of 400 students in my general course.Halfway through my second term when I was considering whether or not to come back in the fall,I went on the Internet and came across Americorp.Then I joined in an organization,and that’s what I did last school year.I worked on making roads,building a house,serving as a teacher’s assistant and working as a camp officer in several projects in South Carolina and Florida.It’s been a great experience,and I’ve almost learned more than what I could have in college since I didn’t really want to be at that school and wasn’t interested in my major anyway,I thought this was better for me.After 1,700 hours of service I received 4,750 dollars.I can use that to pay off the money I borrowed from the bank or for what is needed when I go back to school this fall at Columbus State in Ohio.Classes are smaller there and I’ll be majoring in German education.After working with the kids,now I know,I want to be a teacher.1、Who is the man talking about now?A.His girlfriend.B.His sister.C.His mother.2、What are they talking about?A.A traffic accident.B.A fire.C.A crime.3、Where does the conversation most probably take place?A.At a bookshop.B.At a kitchen.C.At a bank.4、Who was injured?A.George.B.George’s wife.C.George’s wife’s father.5、What do we learn from the conversation?A.Tony could not continue the experiment.B.Tony finished the experiment last night.C.Tony will go on with his experiment.第二节(共15小题,每小题1分)听下面5段对话或独白。