中央電大物流管理專業(yè)《物流學(xué)概論》練習(xí)題答案

《中央電大物流管理專業(yè)《物流學(xué)概論》練習(xí)題答案》由會員分享，可在線閱讀，更多相關(guān)《中央電大物流管理專業(yè)《物流學(xué)概論》練習(xí)題答案（6頁珍藏版）》請在裝配圖網(wǎng)上搜索。

1、《物流學(xué)概論》練習(xí)題答案 《職業(yè)技能實(shí)訓(xùn)一》 物流管理專業(yè)《物流學(xué)概論》練習(xí)題答案 1、 物流系中唯一的靜態(tài)環(huán)節(jié)是（）。答：存儲功能 2、流能過種的商業(yè)交易與物流的分離是由于（）造成的。答：效率經(jīng)濟(jì) 3、 被稱為“第一利潤源”的是。答：資源領(lǐng)域 4、信息管理技術(shù)為物流創(chuàng)造了（）功能實(shí)現(xiàn)的技術(shù)環(huán)境。答：虛擬 5、創(chuàng)造商品的空間效益，實(shí)現(xiàn)其使用價值的環(huán)節(jié)是（）。答：運(yùn)輸 6、生產(chǎn)物流管理的核心是物料的（）。答：運(yùn)行時間成本 7、有物流而無商流的是（）。答：企業(yè)內(nèi)部高撥物流 8、體現(xiàn)集裝化物流的技術(shù)指標(biāo)是（）。答：運(yùn)輸包裝系列尺 9、包裝、裝卸、搬運(yùn)、儲存、運(yùn)輸、配送、信息等

2、屬于（）。答：物流系統(tǒng)的功能要素 10、銷售物流的直接銷售渠道是制造商（）。答：建立銷售網(wǎng)絡(luò)，經(jīng)營產(chǎn)品銷售 11、根據(jù)供應(yīng)鏈容量與用戶需求的關(guān)系可以把供應(yīng)鏈分為：（）。答：平衡供應(yīng)鏈和傾斜供應(yīng)鏈 12、包裝一般可分為商業(yè)包裝和（）。答：運(yùn)輸包 13、物流最重要的經(jīng)濟(jì)性指標(biāo)是物流設(shè)施與設(shè)備的（）比率。答：容積利用 14、已在收發(fā)貨區(qū)臺車上狀態(tài)的活性指數(shù)是（）。答：3 15、客戶價值不是（）價值，而是客戶購買的預(yù)期與滿足感。答：貨幣 16、以下不屬于物流控制要素管理的是（）。答：物流戰(zhàn)略管理 17、利用計算機(jī)系統(tǒng)管理各種與地域、空間相關(guān)的信息，在顯示器上對地圖進(jìn)行任意圖層入大、縮小

3、與調(diào)用，對地理要素和運(yùn)輸工具進(jìn)行直觀顯示的是（）。答：GIS 18、倉儲裝備的核心是（）。答：貨架 19集裝裝備的最大優(yōu)點(diǎn)在于（）。答：減少裝卸次數(shù) 20、條形碼技術(shù)屬于（）。答：物流信息標(biāo)志與采集技術(shù) 21、電子數(shù)據(jù)交換技術(shù)的簡稱是（）。答：E 22、在交通運(yùn)輸領(lǐng)域其經(jīng)營的對象分為人和物兩大類。其中：“物”統(tǒng)稱為（）。答：貨物 23、具有使物流的職能更明確，能夠擴(kuò)大企業(yè)物流經(jīng)營的比重，增加企業(yè)物流活動，保證整體生產(chǎn)和營銷的協(xié)調(diào)等優(yōu)點(diǎn)的組織結(jié)構(gòu)是（）。答：功能獨(dú)立型物流組織 24、集裝箱聯(lián)運(yùn)業(yè)屬于現(xiàn)代物流行業(yè)中的（）。答：通運(yùn)業(yè) 25、對客戶實(shí)行有差別的客戶服務(wù)，帶領(lǐng)自己的客戶

4、群和其它物流企業(yè)，將其所在的整個物流市場推上新的服務(wù)平臺的階段是（）。答：市場創(chuàng)新階段 26、物流系統(tǒng)化的目標(biāo)（5S）中的“speed”。答：快捷性 27、物流質(zhì)量具體包含以下內(nèi)容：（）、物品質(zhì)量、工作質(zhì)量、工程質(zhì)量。答：客戶服務(wù)質(zhì)量 28、反映了倉庫的最大存儲能力的參數(shù)是（）。答：倉容 29、逆向物流由于（）成為社會物流與企業(yè)物流的結(jié)合。答：環(huán)境經(jīng)濟(jì)的要求 30、對一般客戶群提供（）服務(wù)。答：無差別一致性 31、物流基礎(chǔ)模數(shù)尺寸為（）。答：600mmX 400mm 32、在產(chǎn)品和笛聲分類中，屬于開民過程步驟的是（）。答：以上都不是 33、由船舶、航空器載運(yùn)入境并由原裝運(yùn)輸工具

5、載運(yùn)出境的貨物是。答：通運(yùn)貨物 34、在現(xiàn)代制造業(yè)中，物流環(huán)節(jié)的（）超過制造環(huán)節(jié)的加工成本。答：1運(yùn)輸和倉儲成本2物料運(yùn)行時間成本 35、實(shí)行網(wǎng)狀責(zé)任制的是（）。答： 《聯(lián)運(yùn)單證統(tǒng)一規(guī)則》 36、以信息控制將傳統(tǒng)的垂直分離功能運(yùn)作整合為橫向平衡管理的是（）。答：物流一體化 37、供應(yīng)物流過程：選擇采購物品；（）廠內(nèi)物流。答：廠外物流 38、物流信息系統(tǒng)是（）。答：物流控制和物流執(zhí)行網(wǎng)絡(luò) 39、克服產(chǎn)品生產(chǎn)與消費(fèi)在時間上拼成工，使物資產(chǎn)生時間上的效果的環(huán)節(jié)是（）。答：倉儲 40、裝入小于物流模數(shù)尺寸以下的箱內(nèi)物品裝卸搬運(yùn)活到性指數(shù)是（）。答：1 41、（）的數(shù)量占總客戶數(shù)量比例6

6、0%，所創(chuàng)造的利潤占企業(yè)總利潤的10%。答：一般客戶 42、將供應(yīng)鏈劃分為不同類型的基本標(biāo)準(zhǔn)是（）。答：市場變動與主導(dǎo)成員平衡能力 43、適用于海上運(yùn)輸合同，而不適用于航次租船合同的規(guī)則是（）。答：《漢堡規(guī)則》 44、多式聯(lián)運(yùn)的法律基礎(chǔ)是明確（）之間的責(zé)任與權(quán)利。答：承運(yùn)人與聯(lián)運(yùn)人 45、物流成本控制的對象是（）。答：投入與產(chǎn)出的比較 46、進(jìn)口貨物的收貨人自運(yùn)輸工具申報進(jìn)境之日起超過（）未向海關(guān)申報的，其進(jìn)口貨物由海關(guān)提取。答：3個月 47、產(chǎn)權(quán)交易是（）。答：有商流而無物流 48、E。答：物流信息傳輸技術(shù) 49、物流信息管理、物流成本管理和物流質(zhì)量管理屬于（）。答：物流控制

7、要素管理 50、適合于外部環(huán)境較為穩(wěn)定、采用常規(guī)技術(shù)、重視內(nèi)部運(yùn)營效率、操作人員素質(zhì)比較好的中型規(guī)模企。答：功能集合型物流組織 51、物流質(zhì)量管理的核心是（）。答：減少物流過程中的貨物損失率 52、在物流客戶戰(zhàn)略的階段中，其中物流企業(yè)應(yīng)在控制的范圍內(nèi)，向顧客提供無差別的基本服務(wù)的。答：市場進(jìn)入階段 53、物流成本支出與物流服務(wù)水平是（）關(guān)系。答：非線性 54、供應(yīng)鏈?zhǔn)菄@（）建立的穩(wěn)定商業(yè)關(guān)系。答：核心成員企業(yè) 55、（）占全部信裝箱總數(shù)80%以上。答：雜貨集裝箱 56、配貨包裝的標(biāo)識常有標(biāo)記和（）兩大類。答：標(biāo)志 57、在配送中心儲存貨物，根據(jù)用戶的需要進(jìn)行配送，叫做（）。答

8、：儲存配送模式 58、（）不是生活消費(fèi)品配送網(wǎng)絡(luò)的特點(diǎn)。答：配送系統(tǒng)精度要求稍低 59、關(guān)于物和流的概念和定義，說法錯誤的有（）。答：B交通運(yùn)輸領(lǐng)域中，物流學(xué)中的“物”指的是物品C物流的“流”，既是指流通 60、保管的經(jīng)濟(jì)性表現(xiàn)為（）。答：A規(guī)模經(jīng)濟(jì)性C客戶多樣性D作業(yè)靈活性 61、關(guān)于供應(yīng)鏈物流的說法，正確的有（）。答：C信息共享是供應(yīng)鏈動作的基礎(chǔ)D物流信息系統(tǒng)對復(fù)雜供應(yīng)管理非常重要 62、物流的實(shí)體功能，說法錯誤的有（）。答：A包裝與裝卸搬運(yùn)C運(yùn)輸與配送D倉儲與流通加工 63、關(guān)于物流系統(tǒng)的功能，說法錯誤的有（）。答：A單一的運(yùn)輸或包裝可以稱之為物流B配送功能在物流系統(tǒng)得所有動

9、態(tài)功能中是核心功能D配送是運(yùn)輸中的一個組成部分 64、物流標(biāo)準(zhǔn)化的核心內(nèi)容是集裝化，包括（）。答：B運(yùn)輸包裝系列尺寸C托盤標(biāo)準(zhǔn)化D集裝箱標(biāo)準(zhǔn)尺寸 65、以下屬于管理層的信息管理的是（）。答：A成本核算C流通價格規(guī)劃 66、關(guān)于企業(yè)生產(chǎn)物流的說法，不正確的有（）。答：A物流過程的特點(diǎn)是企業(yè)物流最本質(zhì)的特點(diǎn)C企業(yè)生產(chǎn)物流過程具有很強(qiáng)的隨機(jī)性 67、根據(jù)對公司的價值，客戶分為（）。答：B一般客戶C潛力客戶D關(guān)鍵客戶 68、集裝箱標(biāo)準(zhǔn)的主要內(nèi)容是（）。答：A屬于第一系列B具有13種箱型C TEU與FEU主要箱型D 最大總承重不超過30t 69、現(xiàn)代企業(yè)物流管理一體化發(fā)展根源于（）。答：

10、B制造業(yè)結(jié)構(gòu)變化C全球經(jīng)濟(jì)一體化D信息處理商業(yè)化 70、從傳統(tǒng)的實(shí)體配送到現(xiàn)代物流活動，物流管理了（）階段。答：B產(chǎn)品物流C一體化物流D供應(yīng)鏈管理 71、按物流系統(tǒng)性質(zhì)分類的是（）。答：C社會物流D企業(yè)物流 72、物流系統(tǒng)的物質(zhì)基礎(chǔ)要素包括。答：A物流作業(yè)管理層B物流執(zhí)行管理層C 物流職能管理層D物流決策管理層 73、物流系統(tǒng)的物質(zhì)基礎(chǔ)要素包括（）。答：A物流設(shè)施B物流裝備C物流工具D信息技術(shù) 74、根據(jù)供應(yīng)鏈存在的穩(wěn)定性可以供應(yīng)為（）。答：A穩(wěn)定供應(yīng)鏈B動態(tài)供應(yīng)鏈 75、潛力客戶，以下描述正確的是（）。答：A數(shù)量比例占30% B 企業(yè)利潤比例占30% D 客戶目標(biāo)是客戶價值提高

11、 76、屬于特殊附加險的是（）。答：A黃曲霉素險B拒收險D艙面險 77、屬于物流的經(jīng)濟(jì)價值的是（）。答：A時間價值B場所價值C流通加工附加價值 78、關(guān)于第三方物流與第四方物流區(qū)別描述正確的是（） 。答：B第四方物流能夠提供比第三方物流范圍更廣的服務(wù)C第四方物流是物流軟件的運(yùn)營者D第三方物流是物流硬件服務(wù)供應(yīng)商 79、供應(yīng)鏈有兩種不同類型的功能。答：B市場中介功能C物理功能 80、通過物流理論的研究，物流概念產(chǎn)生的原因的是（）。答：C經(jīng)濟(jì)原因D軍事原因 81、以下屬于操作信息管理的是（）答;A單征信息的傳輸與監(jiān)控B價格的確定C業(yè)務(wù)狀態(tài)信息的追蹤與查詢 82、以下關(guān)于出口商品檢驗(yàn)的

12、法律責(zé)任描述準(zhǔn)確的是（） 。答：A將必須經(jīng)商檢機(jī)構(gòu)檢驗(yàn)的進(jìn)口商品未報經(jīng)檢驗(yàn)而擅自銷售或使用的，由商檢機(jī)構(gòu)沒收B未經(jīng)國家商檢部門許可，擅自從事進(jìn)出口商品檢驗(yàn)鑒定業(yè)務(wù)的，由商檢機(jī)構(gòu)責(zé)令停止C進(jìn)口或出口屬于摻雜摻假、以假充真、以次充好的商品，由商檢機(jī)構(gòu)責(zé)令停止進(jìn)口 83、供應(yīng)鏈管理的特征有（）。答：A動態(tài)性B復(fù)雜性C面向用戶需求D交叉性 84、關(guān)于物和流的概念和定義，說法錯誤的有（）。答：B交通運(yùn)輸領(lǐng)域中，物流學(xué)中的“物”指的是物品C物流的：“流”，既是指流通 85、保管的經(jīng)濟(jì)性表現(xiàn)為（）。答：C客戶多樣性D作業(yè)靈活性 86、關(guān)于供應(yīng)鏈物流的說法，正確的有（）答:C信息共享是供應(yīng)鏈動作的基

13、礎(chǔ)D物流信息系統(tǒng)對復(fù)雜供應(yīng)鏈的管理非常重要 87、物流的實(shí)體功能要素由（）組成。。答：C運(yùn)輸與配送D倉儲與流通加工 88、關(guān)于物流系統(tǒng)的功能，說法錯誤的有（）。答：B配送功能在物流系統(tǒng)得所有動態(tài)功能中是核心功能C存儲功能在物流體系統(tǒng)是唯一的靜態(tài)環(huán)節(jié) 89、物流化的核心內(nèi)容是集裝化，包括（）答：B運(yùn)輸包裝系列尺寸C托盤標(biāo)準(zhǔn)化D集裝箱標(biāo)準(zhǔn)尺寸 90、以下屬于管理層的信息管理的是（）。答：A成本核算C流通價格規(guī)劃D運(yùn)輸高度計劃信息 91、關(guān)于企業(yè)生產(chǎn)我省的說法，不正確的有（）。答：A物流過程的特點(diǎn)是企業(yè)物流最本質(zhì)的特點(diǎn)C企業(yè)生產(chǎn)物流過程具有很強(qiáng)的隨機(jī)性 92、根據(jù)對公司的價值，客戶分為（

14、）。答：B一般客戶C潛力客戶D關(guān)鍵客戶 93、集裝箱標(biāo)準(zhǔn)的主要內(nèi)容是（）。答：A屬于第一系列B具有13種箱型 C TEU與FEU為主要箱型D最大總承重不超過30t 94、采購調(diào)查的主要項(xiàng)目是（）。答：A采購系統(tǒng)C所購商品 95、詢問調(diào)查技術(shù)包括（）。答：A自由問答法B二項(xiàng)與多項(xiàng)選擇法C順位法D評定法 96、對現(xiàn)有供應(yīng)商的考評指標(biāo)是（）。答：A質(zhì)量與供應(yīng)指標(biāo)C經(jīng)濟(jì)指標(biāo)D服務(wù)指標(biāo) 97、建立健全采購質(zhì)量標(biāo)準(zhǔn)化體系，才能保證采購工作有據(jù)可依，其標(biāo)準(zhǔn)包括（）。答：A崗位標(biāo)準(zhǔn)C操作標(biāo)準(zhǔn) 98、對供應(yīng)商實(shí)際的檢驗(yàn)活動包括（）。答：A完工檢驗(yàn)B進(jìn)貨檢驗(yàn)C工序檢驗(yàn) 99、采購市場調(diào)查方法有（）。

15、答：A詢問法C觀察法D實(shí)驗(yàn)法 100、采購市場調(diào)查的定性預(yù)測方法是（）。答：A 類推法與專家意見法B局部市場統(tǒng)計與總體估計法C用戶調(diào)查與經(jīng)驗(yàn)判斷法 101、下列關(guān)于采購制度的表述，不正確的是（ ）。答：C集中式的采購制度，可以縮短采購流程D企業(yè)用于多個生產(chǎn)機(jī)構(gòu)，產(chǎn)品品種類似，宜采用分散式采購制度 請您刪除一下內(nèi)容，O(∩_∩)O謝謝?。?！2016年中央電大期末復(fù)習(xí)考試小抄大全，電大期末考試必備小抄，電大考試必過小抄Acetylcholine is a neurotransmitter released from nerve endings (terminals) in both the

16、 peripheral and the central nervous systems. It is synthesized within the nerve terminal from choline, taken up from the tissue fluid into the nerve ending by a specialized transport mechanism. The enzyme necessary for this synthesis is formed in the nerve cell body and passes down the axon to its e

17、nd, carried in the axoplasmic flow, the slow movement of intracellular substance (cytoplasm). Acetylcholine is stored in the nerve terminal, sequestered in small vesicles awaiting release. When a nerve action potential reaches and invades the nerve terminal, a shower of acetylcholine vesicles is rel

18、eased into the junction (synapse) between the nerve terminal and the ‘effector’ cell which the nerve activates. This may be another nerve cell or a muscle or gland cell. Thus electrical signals are converted to chemical signals, allowing messages to be passed between nerve cells or between nerve cel

19、ls and non-nerve cells. This process is termed ‘chemical neurotransmission’ and was first demonstrated, for nerves to the heart, by the German pharmacologist Loewi in 1921. Chemical transmission involving acetylcholine is known as ‘cholinergic’. Acetylcholine acts as a transmitter between motor nerv

20、es and the fibres of skeletal muscle at all neuromuscular junctions. At this type of synapse, the nerve terminal is closely apposed to the cell membrane of a muscle fibre at the so-called motor end plate. On release, acetylcholine acts almost instantly, to cause a sequence of chemical and physical e

21、vents (starting with depolarization of the motor endplate) which cause contraction of the muscle fibre. This is exactly what is required for voluntary muscles in which a rapid response to a command is required. The action of acetylcholine is terminated rapidly, in around 10 milliseconds; an enzyme

22、(cholinesterase) breaks the transmitter down into choline and an acetate ion. The choline is then available for re-uptake into the nerve terminal. These same principles apply to cholinergic transmission at sites other than neuromuscular junctions, although the structure of the synapses differs. In t

23、he autonomic nervous system these include nerve-to-nerve synapses at the relay stations (ganglia) in both the sympathetic and the parasympathetic divisions, and the endings of parasympathetic nerve fibres on non-voluntary (smooth) muscle, the heart, and glandular cells; in response to activation of

24、this nerve supply, smooth muscle contracts (notably in the gut), the frequency of heart beat is slowed, and glands secrete. Acetylcholine is also an important transmitter at many sites in the brain at nerve-to-nerve synapses. To understand how acetylcholine brings about a variety of effects in diffe

25、rent cells it is necessary to understand membrane receptors. In post-synaptic membranes (those of the cells on which the nerve fibres terminate) there are many different sorts of receptors and some are receptors for acetylcholine. These are protein molecules that react specifically with acetylcholin

26、e in a reversible fashion. It is the complex of receptor combined with acetylcholine which brings about a biophysical reaction, resulting in the response from the receptive cell. Two major types of acetylcholine receptors exist in the membranes of cells. The type in skeletal muscle is known as ‘nico

27、tinic’; in glands, smooth muscle, and the heart they are ‘muscarinic’; and there are some of each type in the brain. These terms are used because nicotine mimics the action of acetylcholine at nicotinic receptors, whereas muscarine, an alkaloid from the mushroom Amanita muscaria, mimics the action o

28、f acetylcholine at the muscarinic receptors. Acetylcholine is the neurotransmitter produced by neurons referred to as cholinergic neurons. In the peripheral nervous system acetylcholine plays a role in skeletal muscle movement, as well as in the regulation of smooth muscle and cardiac muscle. In the

29、 central nervous system acetylcholine is believed to be involved in learning, memory, and mood. Acetylcholine is synthesized from choline and acetyl coenzyme A through the action of the enzyme choline acetyltransferase and becomes packaged into membrane-boundvesicles. After the arrival of a nerve si

30、gnal at the termination of an axon, the vesicles fuse with the cell membrane, causing the release of acetylcholine into thesynaptic cleft. For the nerve signal to continue, acetylcholine must diffuse to another nearby neuron or muscle cell, where it will bind and activate areceptorprotein. There are

31、 two main types of cholinergic receptors, nicotinic and muscarinic. Nicotinic receptors are located at synapses between two neurons and at synapses between neurons and skeletal muscle cells. Upon activation a nicotinic receptor acts as a channel for the movement of ions into and out of the neuron, d

32、irectly resulting indepolarizationof the neuron. Muscarinic receptors, located at the synapses of nerves with smooth or cardiac muscle, trigger a chain of chemical events referred to as signal transduction. For a cholinergic neuron to receive another impulse, acetylcholine must be released from the

33、receptor to which it has bound. This will only happen if the concentration of acetylcholine in the synaptic cleft is very low. Low synaptic concentrations of acetylcholine can be maintained via a hydrolysis reaction catalyzed by the enzyme acetylcholinesterase. This enzyme hydrolyzes acetylcholine i

34、nto acetic acid and choline. If acetylcholinesterase activity is inhibited, the synaptic concentration of acetylcholine will remain higher than normal. If this inhibition is irreversible, as in the case of exposure to many nerve gases and some pesticides, sweating, bronchial constriction, convulsion

35、s, paralysis, and possibly death can occur. Although irreversible inhibition is dangerous, beneficial effects may be derived from transient (reversible) inhibition. Drugs that inhibit acetylcholinesterase in a reversible manner have been shown to improve memory in some people with Alzheimers disease

36、. abstract expressionism, movement of abstract painting that emerged in New York City during the mid-1940s and attained singular prominence in American art in the following decade; also called action painting and the New York school. It was the first important school in American painting to declare

37、its independence from European styles and to influence the development of art abroad. Arshile Gorky first gave impetus to the movement. His paintings, derived at first from the art of Picasso, Mir, and surrealism, became more personally expressive. Jackson Pollocks turbulent yet elegant abstract pa

38、intings, which were created by spattering paint on huge canvases placed on the floor, brought abstract expressionism before a hostile public. Willem de Koonings first one-man show in 1948 established him as a highly influential artist. His intensely complicated abstract paintings of the 1940s were f

39、ollowed by images of Woman, grotesque versions of buxom womanhood, which were virtually unparalleled in the sustained savagery of their execution. Painters such as Philip Guston and Franz Kline turned to the abstract late in the 1940s and soon developed strikingly original styles—the former, lyrical

40、 and evocative, the latter, forceful and boldly dramatic. Other important artists involved with the movement included Hans Hofmann, Robert Motherwell, and Mark Rothko; among other major abstract expressionists were such painters as Clyfford Still, Theodoros Stamos, Adolph Gottlieb, Helen Frankenthal

41、er, Lee Krasner, and Esteban Vicente. Abstract expressionism presented a broad range of stylistic diversity within its largely, though not exclusively, nonrepresentational framework. For example, the expressive violence and activity in paintings by de Kooning or Pollock marked the opposite end of th

42、e pole from the simple, quiescent images of Mark Rothko. Basic to most abstract expressionist painting were the attention paid to surface qualities, i.e., qualities of brushstroke and texture; the use of huge canvases; the adoption of an approach to space in which all parts of the canvas played an e

43、qually vital role in the total work; the harnessing of accidents that occurred during the process of painting; the glorification of the act of painting itself as a means of visual communication; and the attempt to transfer pure emotion directly onto the canvas. The movement had an inestimable influe

44、nce on the many varieties of work that followed it, especially in the way its proponents used color and materials. Its essential energy transmitted an enduring excitement to the American art scene. Science and technology is quite a broad category, and it covers everything from studying the stars and

45、 the planets to studying molecules and viruses. Beginning with the Greeks and Hipparchus, continuing through Ptolemy, Copernicus and Galileo, and today with our work on the International Space Station, man continues to learn more and more about the heavens. From here, we look inward to biochemistry

46、and biology. To truly understand biochemistry, scientists study and see the unseen bystudying the chemistry of biological processes. This science, along with biophysics, aims to bring a better understanding of how bodies work – from how we turn food into energy to how nerve impulses transmit.analyti

47、c geometry, branch ofgeometryin which points are represented with respect to a coordinate system, such asCartesian coordinates, and in which the approach to geometric problems is primarily algebraic. Its most common application is in the representation of equations involving two or three variables a

48、s curves in two or three dimensions or surfaces in three dimensions. For example, the linear equationax+by+c=0 represents a straight line in thexy-plane, and the linear equationax+by+cz+d=0 represents a plane in space, wherea, b, c,anddare constant numbers (coefficients). In this way a geometric pro

49、blem can be translated into an algebraic problem and the methods of algebra brought to bear on its solution. Conversely, the solution of a problem in algebra, such as finding the roots of an equation or system of equations, can be estimated or sometimes given exactly by geometric means, e.g., plotti

50、ng curves and surfaces and determining points of intersection. In plane analytic geometry a line is frequently described in terms of its slope, which expresses its inclination to the coordinate axes; technically, the slopemof a straight line is the (trigonometric) tangent of the angle it makes with

51、thex-axis. If the line is parallel to thex-axis, its slope is zero. Two or more lines with equal slopes are parallel to one another. In general, the slope of the line through the points (x1,y1) and (x2,y2) is given bym= (y2-y1) / (x2-x1). The conic sections are treated in analytic geometry as the cu

52、rves corresponding to the general quadratic equationax2+bxy+cy2+dx+ey+f=0, wherea, b,?…?, fare constants anda, b,andcare not all zero. In solid analytic geometry the orientation of a straight line is given not by one slope but by its direction cosines, λ, μ, and ν, the cosines of the angles the line

53、 makes with thex-, y-,andz-axes, respectively; these satisfy the relationship λ2+μ2+ν2= 1. In the same way that the conic sections are studied in two dimensions, the 17 quadric surfaces, e.g., the ellipsoid, paraboloid, and elliptic paraboloid, are studied in solid analytic geometry in terms of the

54、general equationax2+by2+cz2+dxy+exz+fyz+px+qy+rz+s=0. The methods of analytic geometry have been generalized to four or more dimensions and have been combined with other branches of geometry. Analytic geometry was introduced by RenDescartesin 1637 and was of fundamental importance in the development

55、 of thecalculusby Sir Isaac Newton and G. W. Leibniz in the late 17th cent. More recently it has served as the basis for the modern development and exploitation ofalgebraic geometry. circle, closed plane curve consisting of all points at a given distance from some fixed point, called the center. A c

56、ircle is a conic section cut by a plane perpendicular to the axis of the cone. The term circle is also used to refer to the region enclosed by the curve, more properly called a circular region. The radius of a circle is any line segment connecting the center and a point on the curve; the term is als

57、o used for the length r of this segment, i.e., the common distance of all points on the curve from the center. Similarly, the circumference of a circle is either the curve itself or its length of arc. A line segment whose two ends lie on the circumference is a chord; a chord through the center is th

58、e diameter. A secant is a line of indefinite length intersecting the circle at two points, the segment of it within the circle being a chord. A tangent to a circle is a straight line touching the circle at only one point, the point of contact, or tangency, and is always perpendicular to the radius d

59、rawn to this point. A circle is inscribed in a polygon if each side of the polygon is tangent to the circle; a circle is circumscribed about a polygon if all the vertices of the polygon lie on the circumference. The length of the circumference C of a circle is equal to π (see pi) times twice the rad

60、ius distance r, or C=2πr. The area A bounded by a circle is given by A=πr2. Greek geometry left many unsolved problems about circles, including the problem of squaring the circle, i.e., constructing a square with an area equal to that of a given circle, using only a straight edge and compass; it was

61、 finally proved impossible in the late 19th cent. (see geometric problems of antiquity). In modern mathematics the circle is the basis for such theories as inversive geometry and certain non-Euclidean geometries. The circle figures significantly in many cultures. In religion and art it frequently symbolizes heaven, eternity, or the universe.