学生家庭作业调查报告

圆周率到底是一个什么概念?我知道是周长除以直径.回答具体一点(概念）.并且人们为什么意识到有圆周率的呢? Why don't you visit the Palaca Museum with me?___visit the Palaca Museum,___ ____?(同义句） “why don't you visit the Palace Museum with me?"改同意句 come into to classroom的意思 以五为直角边的勾股数 直角边长为十二的勾股数有哪些 求证：勾股数（勾股定理的正整数解）必定满足三数之积是60的倍数（或证两直角边之积是12的倍数）.1楼2楼实在是太高了，居然是这样来证明的。兄弟佩服。 求一组勾股数,一个直角三角形,一直角边为8,斜边等于直角边加一,这组勾股数为多少也就是8为勾 股为x 弦为x+1 （也可能不存在） I hear that we'll take a school trip next week __.I want to relax myself.A I hope so B I hope not I want to go to Hangzhou next month.的答句A.Have a good day B.That sounds good i'm glad that Peter decided to come to the party because we___him for several years.A.haven't seen B.don't see C.didn't see D.hadn't seen 问：选什么,为什么? ab=ad,ac=ae,∠bad=∠cae,试说明be=cd 已知:AB=AD,AC=AE,∠BAD=∠CAE=90°BF=EF求证:AF⊥CD 椭圆的准线方程是什么? 1、一块圆形地按1：5000画在图纸上,半径为5cm,求这块地的实际面积.2、鸡鸭共140只,鸡的只数比鸭少四分之一,鸡和鸭共多少只? 1.一个酒精瓶,他的瓶身成圆柱形（不包括瓶颈）.已知他的容积为26.4π毫升,当瓶子正放时瓶内的酒精的液面高为6厘米,瓶子倒放时空余部分的高为2厘米.问：瓶内有酒精多少毫升?2.甲乙两个圆 we saw him walk into the classroom 改为被动语态 点A（-1,2）关于y轴对称点的坐标是_______,关于原点堆成的点表做是_______,关于x轴对称点的坐标是_______.点M（x-y,2）与点（3,x+y）关于原点对称,则x=_______,y=_______. I saw him go 什么 the classroom 1.正方形ABCD的各边都平行于坐标轴,A,C分别在直线y=2x和y=1/3x上.若点A在直线y=2x上运动,求B点所在直线的解析式.（老师交的时候好像说设点B坐标为（x.y.）正方形边长为a.这个题拜托讲清楚点）2 What happenend?I saw him rush into the classroom.如果rush变为rushing对吗?为什么? I saw him go into the classroom just now .为什么SAW后的动词不是ING形式呢? 为何sin2xcosπ/6-cos2xsinπ/6=2sin(2x-π/6) Yesterday I saw him ___ the classroom alone.A go B enter C to enter D to go into这里的选项里的To都是动词不定式做宾补吗? 为什么2(cosπ/6×sin2x+cos2xsinπ/6)=2sin(2x+π/6)? √3sin2x+cosx为什么等于2（sin2xcosπ/6+cos2xsinπ/6）其中的√3去哪了?cosπ/6和sinπ/6是怎么来的? 求解2sin2x-2cos2x是怎么得到2倍根号2sin（2x-π/4）, 『急求』1/2sin2x+1/2cos2x怎么等于√2/2sin(2x+π/4)1/2sin2x+1/2cos2x怎么等于√2/2sin(2x+π/4) 需要详细过程.sinxcosx+cosx^2-1/2=1/2sin2x+1/2cos2x=√2/2sin(2x+π/4)希望能把sinxcosx+cosx^2-1/2怎么等于1/2sin2x+1/2cos2x也一 已知三角形的三边长分别是3.8,X；若X的值为偶数,则X的值有?A.6个 B.5个 C.4个 D.3个. 根号6(x+1)=2(x-1)急 求lim x→0 e∧(1/x)的极限. They went to America ____ a year.应该填什么