青霉素和头孢的区别

f(x)=x^2ln(ax)的导数 f(x)=2ln(2-x)+ax^2的导数 为什么分子中的系数要等于零? 在锐角三角形ABC中,求sinA与cosB的关系.是高中必修四的三角函数诱导公式问题. 4√1/8-√3x=√32 微观经济题目 英语好的进来看 如图 给出选项 /> P:黄圆（YyRr）X绿圆（yyRr） F1中黄圆自交后代的表表现型以及比例 (x-a)²=1-2a+a²（直接开平方） 有什么好听的英文歌么 说多点谢谢了, you can get some () (grocer)at the grocer'sthe desk is broken.it needs().(mend)carl is making a () (shop)listshe hasn't () (get)much tea or coffeei like ()(chemist)best at the stationer'sthere is a lot of()(vegetable)?here is card for you with our be 很多的英语题求大神解答 A lot of English people have three names: a first name, a middle name and a family name. Their family name comes last. For example, my full name is James Allan Green. Green is my family name. I have two given names. 经济题 英文 我把题给截图了 因为不能复制 下面是题的link 一言九鼎比喻什么动物 一言九鼎是什么动物 【 】=-=解方程:2x^2+3x-4=5/（2x^2+3x） 假如AaBb自交后代B纯和致死,则F1表现性比,6:2:3:1 为什么, 急.求助写一篇英语memo前题：You are the sales manager and had received complaints about the lack of co-operation between the sales executives in your sales team.Write a memo to your sales staff on the importance of the need to co-operate as 什么叫微观经济 什么是微观经济? 实对称矩阵不同特征值特征向量相互正交,X1+X2-2X3=0怎样解这个方程得到两个特征向量是（-1,1,0）和（2,0,1）?而（1,1,1）也符合这个方程,但（1,1,1）却不是特征向量呢? 请英语高手帮写一篇memo啊我向老板请假 老板批准老板同意写一篇老板的绘制的MEMO 一共是两篇 公共秩序对于公共生活的作用 把9分之7写成分子是56,分数大小不变的分数是 请英语高手帮写一篇memo啊~小女子急用~内容：you are the trainning manaager of a company which has won a large export order.you have be asked to organize foreign language trainning for some your staff.write a memo to staff:explaining w 写出二次型f=x1^2 x2^2-x^32 4x1x2写出二次型对应的矩阵A,求A的特征值及特征向量. 写出二次型f=x^2 x^2-x^2 4x1x2写出二次型对应的矩阵A,求A的特征值及特征向量. 有什么办法可以3个月时间速成英语? 中专在校生可否报考大学英语考级或公共英语考级?如题. 英语四级怎么过要速成3个月内? 写个MEMO（要格式）·You are Head of Personnel at a large international company.You have just appointed Ms Francesca Bianchi as the new Sales Manager at Head Office.write a memo of 60~70 words to Head Office staff:1.announcing Ms binachi's appo 为什么人在月球与地球举起的重力相同 怎么速成英语呢