四千年前的中国我们和

英语翻译布朗是警察画师,他要正确她画出每一个罪犯的画像.Brown is a —— ——.He draws a good picyure of —— ——. 3*33*43=几 脱式计算,能简便算的要简便算. 用所给词的适当形式填空：They have some________（apple tree）.下列各句有一处错误,请改正.1、He doesn't likes cakes._______ _______2、It's my pencils.They are red._______ _______3、What are they?They're at home._______ _____ 二次方程的求解公式x=? 帮忙给出推导过程. 是x关于a b c的一个公式,...二次方程的求解公式x=?帮忙给出推导过程.是x关于a b c的一个公式,有根号,九年级学过.帮帮忙!推导一下!定采纳! 爱数学的朋友,三角形的面积公式怎么来的?二次方程的求根公式怎么来的?公式我知道呢第二位答者请问平行四边形的面积又怎么来啊第四位答者很感谢但矩形的面积怎么来呢如果着我满意了 是不是所有二次方程都满足求根公式,在复数的情况下? 1/3,1/8,1/18,1/33,(1/53) 53分之1 怎么推出来的啊? （x的平方分之x的平方减2x加1）除（x的平方减1）乘x的平方减3x加2分之x的平方加x（帮忙算一下, 用反证法证明：在三角形ABC中,若sinA 锐角三角形ABC中,判断sinA与cosB的大小,并证明 在三角形ABC中,A.B为锐角,sinA=cosB,则这个三角形是什么三角形 在锐角三角形ABC中,给出下列命题①sinA>sinB②cosA＞cosB③sinA＞cosB④sinA＜cosB 选出正确的命题并证明 求四阶行列式1234/2341/3412/4123要有过程和方法！结果无所谓 与四阶行列式（1234）（5678)（0010）（9876）的值相等的三阶行列式是, 四阶行列式 第一行 1234 第二行-1234 -1-234 -1-2-34 请问四阶行列式第一行1234第二行2341第三行3412第四行4123 怎么计算 1.The old woman kept one black dog and two white__________.A.one B.ones C.those D.one's2.Henry___________ be at home because he phoned me from the farm just now.A.mustn't B.isn't able to C.may not D.can't3.____________ India and China are of_________ can i get you a drink?it's really nice of you.but i have got____.A.this B.that C.it D.one A和D为什么选D 这是我疑问的地方 1,（）cool story it isA.what B what a C how D how a2,he always works ()a careleaa wayAin B on C by D with3,the watch i lost yesterday ()in the desk A has found B found C has been found D is found4,Columbus () AMERICA in 1492A find B find out Cinven 三角+三角+三角-方块-方块=12 方块+方块+方块-三角-三角=2 问三角 和 方块 =多少? 已知a,b,c是三角形ABC的三边,若a,b,c的倒数成等差数列,求证角B为锐角.2/b=1/a+1/c2/sinB=1/sinA+1/sinC2/sinB=(sinA+sinC)/sinAsinC所以sinAsinC=-(1/2)[cos(A+C)-cos(A-C)]＞0cos(A+C)-cos(A-C)＜0-cosB-cos(A-C)＜0cosB＞cos(C-A)∵1/ 已知a,b,c是三角形ABC的三边,若a,b,c的倒数成等差数列,求证角B是锐角 已知3的X+2的平方*5的X+2的平方=15的3X-4 1.The price of cell phones _____ recently .A have risen B has been raised C has raised D has lifted2.The next plane ______ is from England.A arriving B to arrive C reaching D to reach3.I'd like to know if it will ______ if I park my car here.A mind B 请教几道初中英语题.要详细解释谢谢!1、 ? the shop ? in the morning? A.Is ,close B.Does , opened C.Does ,closed D.Is ,open 2、 ? begin at 8:00. A.The class B. A class C.Class D. Classes 1：Class3 won the football match!____it be ture?a;May b;Must C;Will D;Can2：____ I have your name?Yes,Smith.S-M-I-T-Ha:must b:may c:will d:need3:Will you ____ finish your homework before 8 o'clock this evening?a:can b:may c:be able to d:able to4:Ei 1.I will wait for Tim ___ he gets back.(答案是as,为什么till不行)A.that B.asC.till D.when2.Although it was so cold ,___ he went out without an overcoat.（答案是C,为毛啊）A.but B.soC.yet D.and3.He's already back to Australia,____?（答 1、How has it been ______there in the last five years?a.working on b.going on c.depending on 2.The fighting_______for a week.a.going on b.continued c,away from 3.He is not from the south._______am I.我觉得是so可答案是nor,为什么? 三角形ABC的三边a,b,c的倒数成等差数列,求证B>π/2度 三角形ABC的三边a,b,c的倒数成等差数列,求证B 在三角形ABC中,角A,角B,∠C的对边分别为a,b,c,若a,b,c三边的倒数成等差数列,求证,∠B