14.(坐标系与参数方程选做题)在极坐标系中,直线l的方程为ρsinθ=3,则点(2,π/6)到直线l的距离为 .
[解析]法1:画出极坐标系易得答案2; 法2:化成直角方程及直角坐标可得答案2.
15.(几何证明选讲选做题)如图4所示,圆O的直径AB=6,C为圆周上一点,BC=3过C作圆的切线l,过A作l的垂线AD,垂足为D, 则∠DAC= .
[解析]由某定理可知,又,
故.
(2007海南、宁夏)
15.几何证明选讲选做题]如图所示,圆O的直径为6,C为圆周上一点。BC=3,过C作圆的切线l,过A作l的垂线AD,垂足为D,则∠DAC=______;线段AE的长为_______。
答案:;3。
解析:根据弦切角等于夹弧所对的圆周角及直角三角形两锐角互余,很容易得到答案; AE=EC=BC=3;
(2007广东文)
14.(不等式选讲选做题)设函数则=_____;若,则x的取值范围是________;
答案:6;
13.(坐标系与参数方程选做题)在平面直角坐标系xOy 中,直线l的参数方程为(参数t∈R),圆C的参数方程为(参数),则圆C的圆心坐标为_______,圆心到直线l的距离为______.
答案:(0,2);.
解析:直线的方程为x+y-6=0,d=;
70、Can you work out what these squiggles mean?
答案:68、事情的结果很不错。69、我一向无法了解她。70、你能辨认出这些潦草的字迹是什么意思吗?
69、I've never been able to work her out. ________________
(1) We must work out a plan as quickly as we can.<制定,拟定,定出>
(2) Have you worked out this problem yet?<算出,估计出>
(3) I can't work out the meaning of the poem.<理解,弄懂,看出>
(4) This map is wrong;I can't work out where we are.<判断,说出,看出>
(5) Things will work out if you will just be patient.<得到圆满解决>
(6) Things have worked out badly.<(情况等)结果是>
(题组训练)英译汉:
68、Things worked out quite well. ________________
(1) The assistant did not take her seriously and advised her to buy two bottles of very expensive wine.<认真对待>
(2) He led the ships down the river to a place where the British army could land safely and take the enemy by surprise.<突然袭击>
(3) I won't take up much of your time.<占去(时间)>
(4) The table takes up too much room.<占去,占据(空间)>
(5) When he left school he took up journalism.<从事某项活动,发展某种爱好>
(6) People should be ready to go to prison for their beliefs,but they should never take up anus to fight.<拿起武器>
(7) When you return to the office the following morning or after the holiday,you can listen to the messages and take any necessary action.<采取必要的行动>
(8) The teacher took up the lesson where he left off yesterday.<继续讲述>
(9) Jean took advantage of the lunch hour to finish her homework.<利用>
(10) I take back what I said.<收回>
(11) Take it easy.The roads are icy.<不要着急>
(12) He is taking over my job while I am on holiday.<接替,接管>
(13) He seemed to take great pride in his work.<对……感到骄傲>
(14) She had taken the trouble to buy the books for me.<费力,不怕麻烦>
(15) I'll take on the work,but I can't tell you exactly when I'll finish it.<从事>
(16) The Great Wall has taken on a new look since the liberation.<呈现>
(17) Is the supermarket taking on any more assistants?<雇用>
67、If you don't know the words,you can ________________ (refer to)a dictionary.
答案:65、turned up 66、turned down 67、turn to
66、His invitation is ________________ (refused).
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