题目

在平面直角坐标系中， 以坐标原点为极点，x轴的非负半轴为极轴建立极坐标系．已知点A的极坐标为，直线l的极坐标方程为ρcos＝a，且点A在直线l上． (1)求a的值及直线l的直角坐标方程； (2)圆C的参数方程为(α为参数)，试判断直线l与圆C的位置关系． 答案：【解】 (1)由点A在直线ρcos＝a上，可得a＝， 所以直线l的方程可化为ρcos θ＋ρsin θ＝2， 从而直线l的直角坐标方程为x＋y－2＝0. (2)由已知得圆C的直角坐标方程为(x－1)2＋y2＝1， 所以圆C的圆心为(1,0)，半径r＝1. 因为圆心C到直线l的距离d＝＝＜1，所以直线l与圆C相交．How to deal successfully with a child who shows outstanding musical ability？It’s not always clear how best to develop and encourage his gift.Many parents may even fail to recognise and respond to their children’s need until frustration explodes into difficult or uncooperative(不合作的) behaviour.And while most schools are equipped to deal with children who are specially able in academic subjects，the musically gifted require special understanding which may not always be available in an ordinary school—especially one where music is regarded as a secondary activity.Such children may well benefit from the education offered by a specialist music school.The five music schools in Britain are a relatively recent introduction.They aim to provide an environment in which gifted children aged between seven and eighteen can develop their skills to the full under the guidance of professional musicians.Children at specialist music schools spend between one third and one half of an average day on musical activities，for example，individual lessons，orchestras，chamber(室内音乐的) groups，voice training，conducting and theory.They also spend several hours a day practising in properly equipped private rooms，sometimes with a teacher.The rest of their time is taken up with the subjects：English，maths，basic sciences and languages.All five British specialist schools are independent，classes are small by normal school standards，with a high teacher/pupil ratio(比率)．Most children attending specialist schools tend to be boarders，leaving home to live，eat and sleep full­time at school.What are the disadvantages？An obvious problem is the cost；the fees are high(￡12,000­￡17,000 a year for boarders)．However，each school will make every effort with scholarships and other forms of financial assistance，to help parents of outstandingly gifted children to find the necessary fees.Secondly，not all parents want to send their children to boarding school，especially at a very early age.Almost all the directors of the specialist schools express doubts about the wisdom of admitting children as young as seven into such an intense and disciplined(守纪律的) environment.They stress，however，that their main aim is to turn out “rounded and well­balanced” individuals.There is little doubt that setting musically gifted children apart from an early age can cause stress.Early signs of musical ability may disappear in their teenage years，while natural competitiveness and the pressure to succeed can lead to a deep sense of failure.But all specialist schools do keep a close watch on the progress of individual pupils，and offer help and advice if needed.【小题1】If a child’s musical ability is not recognized，________.A．the child may misbehaveB．the ability may fade awayC．the child may lose interestD．the parents may become anxious【小题2】What problem may musically gifted children face in ordinary schools?A．Their academic work may suffer.B．Schools lack musical equipment.C．Music is not seen as an important subject.D．Parents and teachers do not work together.【小题3】What makes specialist music schools different from other schools?A．Their working day is longer.B．A range of musical training is offered.C．More than half the day is spent on music.D．The children have mostly one­to­one lessons.【小题4】What do most school directors see as a possible disadvantage for pupils?A．Poor children may not be included.B．They may lose their individuality.C．There may be a discipline problem.D．They may not be mature enough on arrival.