2015年美国数学建模竞赛A题
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Problem A Warmer Days or Sour Grapes ?The high quality of wines(葡萄酒)produced in the Finger Lakes Region(五指湖区)of upstate (北部)New York is widely known. Proximity(接近)to lakes tempers the climate and makes it more suitable for growing several varieties of premium(独特)grapes: R iesling(雷司令), G ewürztraminer(琼瑶浆),C hardonnay(霞多丽), M erlot(梅洛), P inot Noir(黑比诺), and CabernetF ranc(品丽珠). (There are many more, but we will restrict(限制)the discussion to these six to simplify(简化)the modeling.) Each variety has its own preferred “average temperature” range but is also different in its susceptibility(感受性)to diseases and ability to withstand(抵抗)short periods of unusually cold temperature.As our local climate changes, the relative suitability of these varieties will be changing as well. A forward-looking winery(酒厂)has hired your team to help with the long-term planning. You will need to recommenda) the proportion(比例)of the total vineyard(葡萄园)to be used for growing each of the above six varieties;b) and when should these changes be implemented (实施)(based on observed temperatures and/or current market prices for each type of wine).Naturally, the winery is interested in maximizing its annual profit. But since the latter (后者)is weather-dependent, it might vary a lot year-to-year. You are also asked to evaluate the trade-offs (权衡)between optimizing the expected/average case versus the worst(-realistic-)scenario(情景).Things to keep in mind:Climate modeling is complicated(复杂)and predicting the rate of “global warming” is a hotly debated area. For the purposes of this problem, assume that the annual average temperature in Ithaca(伊萨卡), NY will increase by no more than 4°C by the end of this century.It is not all about the average temperature – a short snap(临时)of sub- zero(零度)temperature in late Ferburay or early March (after the vines already started getting used to warmer weather) is far more damaging than the same low temperature would be in the middle of the winter.It takes at least 3 years for a newly planted vine to start producing grapes suitable for winemaking.Problem B Outlook of Car-to-Car TechSAN FRANCISCO -- After more than a decade of research into car-to-car communications, U.S. auto safety regulators took a step forward today by unveiling their plan for requiring cars to have wireless gear that will enable them to warn drivers of danger.These vehicle-to-vehicle (V2V) transmitters and software could save thousands of lives and prevent hundreds of thousands of crashes each year by providing cars with information they never will be able to gather simply from cameras and sensors. “Safety is our top priority, and V2V technology represents the next great advance in saving lives,” Transportation Secretary Anthony Foxx said in an announcement. “This technology could move us from helping people survive crashes to helping them avoid crashes altogether.”Requirement 1: Present a mathematical model to discuss the reduction of the number of traffic accidents and road fatalities/injuries in San Francisco by V2V technology. Requirement 2: Determine the maximum number of cars in San Francisco due to the V2V technology.Requirement 3: Discuss the benefits of V2V technology to alleviate road congestion. Requirement 4: Provide your recommendation to the government.Prblem C Forest FiresOne major environmental concern is the occurrence of forest fires (also called wildfires), which affect forest preservation, bring economical and ecological damage and endanger human lives. Such phenomenon is due to multiple causes (e.g. human negligence and lightnings). Despite an increasing of state expenses to control this disaster, each year millions of forest hectares (ha) are destroyed all around the world.Fast detection is an important element for successful firefighting. Traditional human surveillance is expensive and affected by subjective factors, there has been an emphasis to develop automatic solutions, such as satellite-based, infrared/smoke scanners and local sensors (e.g. meteorological). Propagation models try to describe the future evolution of the forest fire given an initial scenario and certain input parameters. Modeling the dynamical behavior of fire propagation in a forest is helpful for creating scheme to control and fight fire.Requirement 1 Describe several different metrics that could be used to evaluate the effectiveness of fire detection. Could you combine your metrics to make them even more useful for measuring quality?Requirement 2 Model the dynamical behavior of fire spread in a forest. Requirement 3 Discuss the factors to affect fire occurrence. Which factors are the most critical in causing fires. Build mathematical models to predict the burned area of fires using Meteorological Data.Requirement 4 Give y our suggestion for preventing from forest fire and fighting against it.Problem D Wearable Activity RecognitionThe percentage of EU citizens aged 65 years or over is projected to increase from 17.1% in 2008 to 30.0% in 2060. In particular, the number of 65 years old is projected to rise from 84.6 million to 151.5 million, while the number of people aged 80 or over is projected to almost triple from 21.8 million to 61.4 million (EUROSTAT: New European Population projections 2008–2060). It has been calculated that the purely demographic effect of an ageing population will push up health-care spending by between 1% and 2% of the gross domestic product (GDP) of most member states. At first sight this may not appear to be very much when extended over several decades, but on average it would in fact amount to approximately a 25% increase in spending on health care, as a share of GDP, in the next 50 years (European Economy Commission, 2006). The effective incorporation of technology into health-care systems could therefore be decisive in helping to decrease overall public spending on health. One of these emerging health-care systems is daily living physical activity recognition.Daily living physical activity recognition is currently being applied in chronic disease management (Amft & Troter, 2008; Zwartjes, Heida, van Vugt, Geelen, & Veltink, 2010), rehabilitation systems (Sazonov, Fulk, Sazonova, & Schuckers, 2009) and disease prevention (Sazonov, Fulk, Hill, Schutz, & Browning, 2011; Warren et al., 2010), as well as being a personal indicator to health status (Arcelus et al., 2009). One of the principal subjects of the health related applications being mooted is the monitoring of the elderly. For example, falls represent one of the major risks and obstacles to old people’s independence (Najafi, Aminian, Loew, Blanc, & Robert, 2002; Yu, 2008). This risk is increased when some kind of degenerative disease affects them. Most Alzheimer’s patients, for exa mple, spend a long time every day either sitting or lying down since they would otherwise need continuous vigilance and attention to avoid a fall.The registration of daily events, an important task in anticipating and/or detecting anomalous behavior patterns and a primary step towards carrying out proactive management and personalized treatment, is normally poorly accomplished by patients’ families, healthcare units or auxiliary assistants because of limitations in time and resources. Automatic activity-recognition systems could allow us to conduct a completely detailed monitoring and assessment of the individual, thus significantly reducing current human supervision requirements.Most wearable activity recognition systems assume a predefined sensor deployment that remains unchanged during runtime. However, this assumption does not reflect real-life conditions. During the normal use of such systems, users may place the sensors in a position different from the predefined sensor placement. Also, sensors may move from their original location to a different one, due to a loose attachment. Activity recognition systems trained on activity patterns characteristic of a given sensor deployment may likely fail due to sensor displacements.Your task is as follows.(1) Build models to recognize daily living activities.(2) Explore the effects of sensor displacement induced by both the intentionalmisplacement of sensors and self-placement by the user.(3) Verify your recognition models’ toleranc e to sensor displacement.Data Set Information:The REALDISP (REAListic sensor DISPlacement) dataset has been originally collected to investigate the effects of sensor displacement in the activity recognition process in real-world settings. It builds on the concept of ideal-placement, self-placement and induced- displacement. The ideal and mutual-displacement conditions represent extreme displacement variants and thus could represent boundary conditions for recognition algorithms. In contrast, self-placement reflects a users perception of how sensors could be attached, e.g., in a sports or lifestyle application. The dataset includes a wide range of physical activities (warm up, cool down and fitness exercises), sensor modalities (acceleration, rate of turn, magnetic field and quaternions) and participants (17 subjects). Apart from investigating sensor displacement, the dataset lend itself for benchmarking activity recognition techniques in ideal conditions.Dataset summary:#Activities: 33#Sensors: 9#Subjects: 17#Scenarios: 3ACTIVITY SET:A1: WalkingA2: JoggingA3: RunningA4: Jump upA5: Jump front & backA6: Jump sidewaysA7: Jump leg/arms open/closedA8: Jump ropeA9: Trunk twist (arms outstretched)A10: Trunk twist (elbows bent)A11: Waist bends forwardA12: Waist rotationA13: Waist bends (reach foot with opposite hand)A14: Reach heels backwardsA15: Lateral bend (10_ to the left + 10_ to the right)A16: Lateral bend with arm up (10_ to the left + 10_ to the right)A17: Repetitive forward stretchingA18: Upper trunk and lower body opposite twistA19: Lateral elevation of armsA20: Frontal elevation of armsA21: Frontal hand clapsA22: Frontal crossing of armsA23: Shoulders high-amplitude rotationA24: Shoulders low-amplitude rotationA25: Arms inner rotationA26: Knees (alternating) to the breastA27: Heels (alternating) to the backsideA28: Knees bending (crouching)A29: Knees (alternating) bending forwardA30: Rotation on the kneesA31: RowingA32: Elliptical bikeA33: CyclingSENSOR SETUP:Each sensor provides 3D acceleration (accX,accY,accZ), 3D gyro (gyrX,gyrY,gyrZ), 3D magnetic field orientation (magX,magY,magZ) and 4D quaternions (Q1,Q2,Q3,Q4). The sensors are identified according to the body part on which is placed respectively:。
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地球资源的消耗速度快,越来越多的人关注人类社会的未来.自1960年以来,已经有许多专家研究可持续发展.然而大多数人的研究对象是整个世界,一个国家或一个地区。
几乎没有人选择48个最不发达国家(LDC)在联合国为研究对象列表。
然而,LDC国家集团共享许多相同的点。
他们的发展道路也有法律的内涵。
本文选择这些国家为研究对象针对发现常规的可持续发展道路。
本文组织如下.第二部分介绍研究的背景和本研究的意义。
第三节描述了我们对可持续发展的理解细节和显示我们的评估系统的建立过程和原理,那么我们估计每一个国家的LDC和获得可持续发展的能力和等级。
第四节提供了一个最糟糕的国家毛里塔尼亚计划指数在第三节。
第五节演示了在第四节的合理性和可用性计划。
最后在第六节总结本文的主要结论和讨论的力量和潜在的弱点。
地球上的资源是有限的。
三大能源石油、天然气和煤炭可再生。
如何避免人类的发展了资源枯竭和实现可持续发展目标是现在的一个热门话题.在过去的两个世纪,发达国家已经路上,先污染,再控制和达到高水平的可持续发展。
发展中国家希望发展和丰富。
然而,因为他们的技术力量和低水平的经济基础薄弱,浪费和低效率的发展在这些国家是正常的.所以本文主要关注如何帮助发展中国家特别是48在联合国最不发达国家实现可持续发展是列表可持续发展的理解是解决问题的关键.可持续发展的定义经历了一个长期发展的过程.在这里,布伦特兰可持续发展委员会的简短定义的"能力发展可持续- — - — - -以确保它既满足现代人的需求又不损害未来的能力代来满足自己的需求"[1]无疑是最被广泛接受的一个在各种内吗定义.这个定义方面发挥了重要作用在很多国家的政策制定的过程.然而,为了证明一个国家的现状是否可持续不可持续的,更具体的定义是必要的更具体的概念,我们认为,如果一个国家的发展是可持续的,它应该有一个基本的目前的发展水平,一个平衡的国家结构和一个光明的未来。
2015数学建模A题论⽂介绍A题太阳影⼦定位摘要本⽂⾸先确定了不同地点不同⽇期的直杆影长的模型,利⽤该模型解决了不同地点不同⽇期直杆影⼦变化和时间的的关系,为分析视频的拍摄地点和⽇期提供了模型上的基础。
对于问题⼀,为了确⽴直杆的影长与时间的关系,建⽴了地球坐标系和天球坐标系,引⼊太阳⾼度⾓、⾚纬、太阳时⾓、时差等参数变量。
利⽤太阳⾼度⾓和时间的关系建⽴了影长和时间的关系模型。
利⽤MATLAB软件求得影长关于时间的变化曲线,从9点到15点影⼦长度先减⼩后增⼤,在北京时间12点14分直杆影长最短,最短为3.5⽶,在北京时间9点直杆影长最长,长度为7.3⽶。
对于问题⼆,结合问题⼀中各参数变量之间的关系,使⽤Bourges算法和太阳⽅位⾓与时间的关系,得到确定直杆所在地点的数学模型,将附件1所给数据带⼊模型,利⽤excel和MATLAB软件进⾏求参数和拟合函数图像,求得直杆所处的可能地点为北纬19.21,东经108.43。
该地点在海南。
或者为南纬3.9412度,东经137.3度。
该地点在为印度尼西亚纳⽐雷附近。
对于问题三,由所给影⼦顶点坐标数据计算出各时间点的太阳⽅位⾓,利⽤excel 软件拟合出太阳⽅位⾓与时间的关系,进⽽确定直杆点的经度,结合问题⼆的数学模型得到直杆地点和⽇期求法的数学模型。
再次通过MATLAB进⾏求参数和拟合函数图像,求出了附件2地点可能为北纬39.88,东经79.7925或南纬39.88,东经79.7925,可能⽇期为:5⽉25号和7⽉20号或1⽉17号和1⽉26号。
对于问题四,提取出视频所有的帧数,等差得选取其中的20张进⾏模拟,利⽤3DMAX 软件仿真出视频的场景,通过测量所建模型中影⼦长度,确定出20组影⼦顶点坐标数据,再⽤问题⼆中所⽤到的模型进⾏求解,得到经纬度为北纬15.2,东经113.9.拍摄地点在海南省的三沙市。
⽤问题三中的模型求解得到拍摄地点纬度为0,东经123.8度在印度尼西亚,⽇期为3⽉21号或10⽉23号。
This Solutions Pamphlet gives at least one solution for each problem on this year’s exam and shows that all the problems can be solved using material normally associated with the mathematics curriculum for students in eighth grade or below. These solutions are by no means the only ones possible, nor are they necessarily superior to others the reader may devise.We hope that teachers will share these solutions with their students. However, the publication, reproduction, or communication of the problems or solutions of the AMC 8 during the period when students are eligible to participate seriously jeopardizes the integrity of the results. Dissemination at any time via copier, telephone, email, internet or media of any type is a violation of the competition rules.Correspondence about the problems and solutions should be addressed to:Prof. Norbert Kuenzi, AMC 8 Chair934 Nicolet AveOshkosh, WI 54901-1634Orders for prior year exam questions and solutions pamphlets should be addressed to:MAA American Mathematics CompetitionsAttn: PublicationsPO Box 471Annapolis Junction, MD 20701© 2015 Mathematical Association of AmericaWe thank the following donors for their generous support of the MAA American Mathematics Competitions, MOSP and the IMOPatron’s CircleAkamai FoundationSimons FoundationWinner’s CircleAmerican Mathematical SocietyThe D.E. Shaw GroupDropboxMathWorksTwo SigmaTudor Investment CorporationAchiever’s CircleArt of Problem SolvingJane Street CapitalMath for AmericaSustainer’s circleAcademy of Applied ScienceArmy Educational Outreach ProgramCollaborator’s CircleAmerican Statistical AssociationCasualty Actuarial SocietyConference Board of the Mathematical SciencesExpii, Inc.IDEA MATHMu Alpha ThetaNational Council of Teachers of MathematicsSociety for Industrial and Applied MathematicsStar League。
A题The world medical association has announced that their new medication could stop Ebola and cure patients whose disease is not advanced. Build a realistic, sensible, and useful model that considers not only the spread of the disease, the quantity of the medicine needed, possible feasible delivery systems, locations of delivery, speed of manufacturing of the vaccine or drug, but also any other critical factors your team considers necessary as part of the model to optimize the eradication of Ebola, or at least its current strain. In addition to your modeling approach for the contest, prepare a 1-2 page non-technical letter for the world medical association to use in their announcement.世界医学协会日前宣布,其新的药物可以阻止埃博拉病毒和治愈患者的疾病,谁的病没有进入晚期。
因此,建立一个现实的、合理的,并且有用的模型是认为制造的疫苗或药物的不仅是这种疾病的传播、所述药物的所需要的数量、可能的可行交付系统、交付地点、制造的疫苗或药物的速度,但也可以是任何你的团队认为有必要为模型做贡献的其他关键因素,以便优化消灭埃博拉病毒或者至少抑制其目前的压力。
比赛时间:美国东部时间:2015年2月5日(星期四)下午8点-2月9日下午8点(共4天)北京时间:2015年2月6日(星期五)上午9点-2月10日上午9点农历:十二月十八~十二月廿二重要说明:●COMAP是所有的规则和政策的最后仲裁者,对不遵循竞赛规则和程序的任何队伍,拥有唯一的自由裁量权,取消参赛资格或拒绝登记。
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比赛之前注册报名1.报名截至时间:2015年2月5日下午2:00 EST。
截止日期后,注册系统将自动关闭,不再接受任何新的注册,没有例外。
2.每支参赛队伍都必须有一位来自参赛机构(institute)的教师担任导师(faculty advisor),不允许学生担任导师。
由指导老师负责为其指导队伍注册报名,每位指导老师可注册的队伍数目没有限制。
PROBLEM A: Eradicating EbolaThe world medical association has announced that their new medication could stop Ebola and cure patients whose diseases not advanced. Build a realistic, sensible, and useful model that considers not only the spread of the disease, the quantity of the medicine needed, possible feasible delivery systems, locations of delivery, speed of manufacturing of the vaccine or drug, but also any other critical factors your team considers necessary as part of the model to optimize the eradication of Ebola, or at least its current strain. In addition to your modeling approach for the contest, prepare a 1-2 page non-technical letter for the world medical association to use in their announcement.A消除埃博拉病毒世界医学协会已经宣布他们的新疗法可以阻止埃博拉疫情和治愈非晚期患者。
构建一个现实的、合理的和有用的模型,不仅要考虑疾病的传播,所需药物的数量,可能且可行的给药系统,给药地点,生产疫苗或药物的速度,而且还要考虑其他关键因素(你的团队认为有必要要考虑的)作为模型的一部分以优化消除埃博拉病毒,或至少是现行毒株。
PROBLEM A: Eradicating EbolaThe world medical association has announced that their new medication could stop Ebola and cure patients whose disease is not advanced. Build a realistic, sensible, and useful model that considers not only the spread of the disease, the quantity of the medicine needed, possible feasible delivery systems, locations of delivery, speed of manufacturing of the vaccine or drug, but also any other critical factors your team considers necessary as part of the model to optimize the eradication of Ebola, or at least its current strain. In addition to your modeling approach for the contest, prepare a 1-2 page non-technical letter for the world medical association to use in their announcement.问题一:根除病毒世界医疗联盟声称,他们的新药物可以制止埃博拉病毒,并且治愈病情没有恶化的患者。
建立一个现实的,明智的,并且有用的模型,需要考虑的不仅是疾病的扩散、所需要的药物、可能并且可行的发放系统、发放的地点、生产疫苗或药物的速度,还有你们队伍认为在优化消灭埃博拉(或至少它的现在的同类血亲)模型之中重要的因素。
嫦娥三号软着陆轨道设计与控制策略摘要在整个“嫦娥三号”软着陆过程中发动机的燃耗问题是整个着陆过程的关键问题之一,其利用率直接影响到整个着陆过程的成果与否,本文主要利用数学建模的方法对整个软着陆过程进行分析,使得整个软着陆过程发动机能耗最优。
针对问题一,首先需建立一个三维立体坐标系,根据牛顿第二定律,结合科氏定律整理得到嫦娥三号在月固定坐标系中的运动方程,再以卫星运行轨道切面为基面建立二维平面坐标系,将嫦娥三号软着陆问题简化为平面几何问题,求解出主减速阶段嫦娥三号水平位移的距离。
通过坐标变换求得位置。
最后根据天体运动规律得到近日点与远日点速度分别为s6226.1。
km.1、skm7006针对问题二,通过寻找一个制导律u,来调整推力的大小和方向,使嫦娥三号在月面实现燃耗最优着陆轨道,应用极大值原理设计这个最优制导律。
在障碍规避过程中,将动力学模型进行进一步简化,忽略了月球的自转角速度等相关因素。
再利用双线性插值的方法求取规则的采样点处的高程值,这样有利于方便的建立障碍检测算法并对着陆区表面的障碍进行提取,最后利用基于平面拟合的障碍检测算法取得着陆区域内某局部区域内的地形平面,我们将利用这个地表平面来对障碍物进行识别,达到安全着陆的目的。
针对问题三,影响制导精度的误差源主要有偏离标准飞行轨迹的初始条件误差和导航与控制传感器误差。
初始条件误差由主制动段以前的任务决定,传感器误差则由导航系统和传感器本身决定,通过建立误差模型,可以很好地对初始状态偏差、传感器测量偏差等不同因素造成的误差进行分析。
关键词:月球着陆轨道能耗最优打靶法最优制导律控制策略一问题重述嫦娥三号于2013年12月2日1时30分成功发射,12月6日抵达月球轨道。
嫦娥三号在着陆准备轨道上的运行质量为2.4t,其安装在下部的主减速发动机能够产生1500N到7500N的可调节推力,其比冲(即单位质量的推进剂产生的推力)为2940m/s,可以满足调整速度的控制要求。
2014-2015年度美国”数学大联盟杯赛“(中国赛区)初赛(十、十一、十二年级)一、选择题(每小题10分,答对加10分,答错不扣分,共100分,请将正确答案A 、B 、C 或者D 写在每题后面的圆括号内。
)正确答案填写示例如下:=-⨯⨯20522 ? (A )A)5 B)15 C)25 D)301. Meg loves her megaphone! The large circular end has a circumference that is the reciprocal of its diameter. What is the area of the circle? ( )A)π14 B) π12 C) 14 D) 122. How many solutions does the equation x x +=233 have? ( )A)0 B)1 C)2 D)43. If y x =-1, which of the following is always true for any value of x ? ( )A) ()()x y -=-2211B) ()()x x y y -=-222211 C) ()()x x y y --=-222211 D) ()()()()x x y y -+=-+22221111 4. Lee the crow ate a grams of feed that was 1% seed, b grams of feed that was 2% seed, and c grams of feed that was 3% seed. If combined, all the feed he ate was 1.5% seed. What is a in terms of b and c ?( )A)b c +3B)b c +3 C)b c +23 D)b c +32 5. If <x 0 and <.x 2001, then x -1 must be ( )A)less than -10B)between-0.1 and 0 C)between 0and 0.1 D) greater than 106. At 9:00 A.M., the ratio of red to black cars in a parking lot was 1 to 5. An hour later the number of red cars had increased by 2, the number of black cars had decreased by 5, and the ratio of red to black cars was 1 to 4. How many black cars were in the lot at 10:00 A.M.? ( )A)13 B)15 C)60 D)657. If x ≠1and x ≠-1, then ()()()x x x x x --++-32241111=( ) A)x -21 B) x +21 C) x -241 D) x -341 8. The Camps are driving at a constant rate. At noon they had driven 300 km.At 3:30 P.M. they had driven 50% further than they had driven by 1:30 P.M.What is their constant rate in km/hr? ( )A)150 B)120 C)100 D)909. The letters in DIGITS can be arranged in how many orders without adjacent I ’s? ( )A)240 B)355 C)600 D)71510. Al, Bea, and Cal each paint at constant rates, and together they are painting a house. Al and Bea togethercould do the job in 12 hours; Al and Cal could to it in 15, and Bea and Cal could do it in 20. How many hours will it take all three working together to paint the house?( )A)8.5 B)9 C)10 D)10.5二、填空题(每小题10分,答对加10分,答错不扣分,共200分)11. What is the sum of the degree-measures of the angles at the outer points ,,,A B C D and E of a five-pointed star, as shown? Answer: . 12. What is the ordered pair of positive integers (,k b ), with the least value of k , which satisfiesk b ⋅⋅=34234?Answer: .13. A face-down stack of 8 playing cards consisted of 4 Aces (A ’s) and 4 Kings (K ’s).After I revealed and then removed the top card, I moved the new top card to thebottom of the stack without revealing the card. I repeated this procedure until thestack without revealing the card. I repeated this procedure until the stack was leftwith only 1 card, which I then revealed. The cards revealed were AKAKAKAK ,in that order. If my original stack of 8 cards had simply been revealed one card at atime, from top to bottom (without ever moving cards to the bottom of the stack),in what order would they have been revealed?Answer: .14. For what value of a is one root of ()x a x a -+++=222120 twice the other root?Answer: .15. Each time I withdrew $32 from my magical bank account, the account ’sremaining balance doubled. No other account activity was permitted. My fifth$32 withdrawal caused my account ’s balance to become $0. With how manydollars did I open that account?Answer: .16. In how many ways can I select six of the first 20 positive integers, disregarding the order in which these sixintegers are selected, so that no two of the selected integers are consecutive integers?Answer: .17. If, for all real ,()()xx f x f x =-21, what is the numerical value of f (3)?Answer: .18. How many pairs of positive integers (without regard to order) have a least common multiple of 540?Answer: .19. If the square of the smaller of consecutive positive integers is x , what is the square of the larger of thesetwo integers, in terms of x ?Answer: .20. A pair of salt and pepper shakers comes in two types: identical and fraternal.Identical pairs are always the same color. Fraternal pairs are the same colorhalf the time. The probability that a pair of shakers is fraternal is p andthat a pair is identical is .q p =-1 If a pair of shakers is of the same color, AE DCBword 格式-可编辑-感谢下载支持 determine, in terms of the variable q alone, the probability that the pair is identical. Answer: .21. As shown, one angle of a triangle is divided into four smaller congruentangles. If the lengths of the sides of this triangle are 84, 98, and 112, as shown,how long is the segment marked x ?Answer: .22. How long is the longer diagonal of a rhombus whose perimeter is 60, if threeof its vertices lie on a circle whose diameter is 25, as shown?Answer: .23. The 14 cabins of the Titanic Mail Boat are numbered consecutively from1 through 14, as are the 14 room keys. In how many different ways canthe 14 room keys be placed in the 14 rooms, 1 per room, so that, for everyroom, the sum of that room ’s number and the number of the key placed inthat room is a multiple of 3?Answer: .24. For some constant b , if the minimum value of ()x x b f x x x b -+=++2222is 12, what is the maximum value of ()f x ? Answer: .25. If the lengths of two sides of a triangle are 60cos A and 25sin A , what is the greatest possible integer-length of the third side?Answer: .26. {}n a is a geometric sequence in which each term is a positive number. If a a =5627, what is the value oflog log log ?a a a +++3132310Answer: . 27. What is the greatest possible value of ()=sin cos ?f x x x ++3412Answer: .28. Let C be a cube. Triangle T is formed by connecting the midpoints of three edges of cube C . What is the greatest possible measure of an angle of triangle T ?Answer: .29. Let a and b be two real numbers. ()sin f x a x b x =++34 and (lg log )f =3105. What is the value of (lg lg )f 3?Answer: .30. Mike likes to gamble. He always bets all his chips whenever the number of chips he has is <=5. He always bets n (10-)chips whenever the number of chips he has is greater than 5 and less than 10. He continues betting until either he has no chips or he has more than 9 chips. For every round, if he bets n chips. The probability that he wins or loses in each round is 50%. If Mike begins with 4 chips, what is the probability that he loses all his chips?Answer: .1129884xword格式-可编辑-感谢下载支持。
What is the value ofProblem2A box contains a collection of triangular and square tiles.There are tiles in the box, containing edges total.How many square tiles are there in the box?Problem3Ann made a3-step staircase using18toothpicks.How many toothpicks does she need to add to complete a5-step staircase?Problem4Pablo,Sofia,and Mia got some candy eggs at a party.Pablo had three times as many eggs as Sofia,and Sofia had twice as many eggs as Mia.Pablo decides to give some of his eggs to Sofia and Mia so that all three will have the same number of eggs.What fraction of his eggs should Pablo give to Sofia?Problem5Mr.Patrick teaches math to students.He was grading tests and found that when hegraded everyone's test except Payton's,the average grade for the class was.After he graded Payton's test,the test average became.What was Payton's score on thetest?The sum of two positive numbers is times their difference.What is the ratio of thelarger number to the smaller number?Problem7How many terms are there in the arithmetic sequence,,,...,,?Problem8Two years ago Pete was three times as old as his cousin Claire.Two years before that, Pete was four times as old as Claire.In how many years will the ratio of their ages be :?Problem9Two right circular cylinders have the same volume.The radius of the second cylinderis more than the radius of the first.What is the relationship between the heights of the two cylinders?Problem10How many rearrangements of are there in which no two adjacent letters are alsoadjacent letters in the alphabet?For example,no such rearrangements could include either or.The ratio of the length to the width of a rectangle is:.If the rectangle hasdiagonal of length,then the area may be expressed as for some constant.What is?Problem12Points and are distinct points on the graph of.What is?Problem13Claudia has12coins,each of which is a5-cent coin or a10-cent coin.There are exactly17different values that can be obtained as combinations of one or more of her coins.How many10-cent coins does Claudia have?Problem14Problem15Consider the set of all fractions where and are relatively prime positive integers. How many of these fractions have the property that if both numerator anddenominator are increased by,the value of the fraction is increased by?Problem16If,and,what is the value of?Problem17A line that passes through the origin intersects both the line and the line.The three lines create an equilateral triangle.What is the perimeter of the triangle?Problem18Hexadecimal(base-16)numbers are written using numeric digits through as well as the letters through to represent through.Among the firstpositive integers,there are whose hexadecimal representation contains onlynumeric digits.What is the sum of the digits of?Problem19The isosceles right triangle has right angle at and area.The raystrisecting intersect at and.What is the area of?Problem20A rectangle has area and perimeter,where and are positive integers.Which of the following numbers cannot equal?Problem21Tetrahedron has,,,,,and.What is the volume of the tetrahedron?Problem22Eight people are sitting around a circular table,each holding a fair coin.All eight people flip their coins and those who flip heads stand while those who flip tails remain seated.What is the probability that no two adjacent people will stand?Problem23The zeros of the function are integers.What is the sum of the possible values of?Problem24For some positive integers,there is a quadrilateral with positive integerside lengths,perimeter,right angles at and,,and.Howmany different values of are possible?Problem25Let be a square of side length.Two points are chosen independently at random onthe sides of.The probability that the straight-line distance between the points is atleast is,where,,and are positive integers with.Whatis?。