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已知A+B=2/3π,则cos^2A+cos^2B的最大值如题 已知a>0,b>0,1/a+3/b=1,则a+2b的最大值A.7+2根号6 B.2根号3 C.7+2根号3 D.14 向井底大喊 回声一个同学向一个枯井的井底大喊一声,经1.5秒听到回声,求枯井深度? 一道关于回声的物理题?莫测量员是这样利用回声来测量距离的：他站在两平行峭壁间的某一位置鸣枪,经过1.00s第一次听到回声,又经0.50s再次听到回声.已知声音在空气中的传播速度为340m/s,则 甲数的3分之2等于乙数的5分之3等于丙数的倒数,请将甲,乙、丙按从大到小排列? 甲x1又3分之2=丙除以8分之7=乙（甲乙丙均不等于0）,将这三个数从小到大排列 有甲,乙,丙三个数,甲是乙的七分之四,甲是丙的五分之二,把三数按从小到大排序,并写出思考理由. 成语英文怎么拼 带拼的成语 这个题成语怎么拼? 卓 有 成 效成语怎么拼 水与什么反应可生成黑色物质 七年级下册历史人物和主要事迹,按时间顺序整理! try to think of others,not only youeslf的意思 写出七年级上册的历史典故及历史人物（至少十个） 给我发一份七年级上册的所有历史人物!30分!我至少要30个灌水勿来!非诚勿扰啊! We must think more of others,we must not think only of()(自己)谢谢 You should think_____yourself instead of just obeying others.A of B.to C.by D.for选D怎么理解,"为自己着想"? 英语翻译请各位高手用中文翻译下列一段英语,不要用软件翻译!There is an old Chinese tale about a woman whose only son died.She went to the holy man and said ,”what magical things do you have to being my son back to life?" The 如图,△ABC中,∠ABC和∠ACD的平分线相交于点O.试探索:∠BOC和∠A的关系并证明你的结论.今晚就要,不要太迟! 如图,三角形ABC,BO、CO平分角ABC和角ACD,试猜想角A与角BOC的关系,并证明你的猜想 小明量得一根竹竿长1.6米.14；00时,他量得竹竿的影长是2米.同时量得旁边一棵大树的影长是12米.这棵大树的高是多少米?【用比例解】这是六年级的题. He is the only person who understands me 为什么用understands而不是understanding呢,不是用非谓语的吗正因为这里是个定语从句才觉得要用现在分词呀 英语选择题This is the only person___understands meAwhomBwhatCwhoseDthat i came only for a person,a person special for me this is the only person __i know in beijing . A who B thatMiss Green is the only person （） can help you with your English.A who B that答案第一个是that第二个是who.到底是看the only用that还是看person用who呢?那要是this is the o 英译中,求帮忙翻译,不要翻译器的We can learn all we need on the InternetI agree with this idea,especially on the subject of learning English.In my class.there are 45 students,and our English lessons last for 50 minutes. That means that we 在△ABC中,∠ACD是△ABC的一个外角,∠ABC,∠ACD的平分线相交于点O,若：∠A=40°,求觉BOC的度数. 英译中,人工翻译,不要翻译器,谢谢Highlighting the immense public interest in the issue, the government website, on which the 3-hour hearing was broadcast live, crashed several times due to unexpected large number of visitors. The rise, th 英语翻译A five-legged Martian has a drawer full of socks,each of which is red,white,or blue,and there are at least five socks of each color.The Martian pulls out one sock at a time without looking.How many socks must the Martian remove from the d 英语翻译1.It was noted that the piece-rated employees were missing time-in and time-out records for all night overtime working hours.Moreover,the monthly rate workers had no time record to track their working hours.Therefore,workers’ actual wor 英语翻译Value Creation Based Cost Management of Real Estate ProjectAbstract—In the increasingly competitive real estate market,the cost management of real estate enterprises has become more and more important.However,in the cost management and