Mathematca 解方程怎么增加解的有效数字

一道英语问题
The conference was organized for all the_____.
A mathematic teachers B mathematics's teachers C mathematics' teachers D mathematics teachers

英语翻译
The recent,apparently successful,prediction by mathematical models of an appearance of El Nino厄尔尼诺现象—the warm ocean flow that periodically develops along the Pacific coast of South America has excited researchers．Jacob Bjerknes pointed out years ago how winds might create either abnormally（反常的） warm or abnormally cold water in the eastern equatorial （赤道附近的） Pacific．Nevertheless,before the creation of the models,no one could explain why conditions should regularly change between appearances of the warm El Nino（厄尔尼诺） and the so-called anti-El Nino．The answer,at least if the current model that links the behavior of the ocean to that of the atmosphere is correct,is to be found in the ocean．
x05It has long been known that during an El Nino,two conditions exist:unusually warm water extends along the eastern Pacific and winds blow from the west into the warmer air rising over the warm water in the east．The contribution of the model is to show that the winds of an El Nino,which raise sea level in the east,send a signal to the west lowering sea level at the same time．According to the model,that signal is created as a negative （负的） Rossby wave,a wave of lower sea level,that moves westward parallel平行 to the equator at 25 to 85 kilometers per day．Taking months to move across the Pacific,Rossby waves march to the western boundary of the Pacific basin,which is modeled as a smooth wall but in reality consists of由...组成 quite irregular island chains．
x05When the waves meet the western boundary,they are reflected,and the model predicts that Rossby waves will be broken into many coastal Kelvin waves carrying the same negative sea-level signal．These eventually shoot急流 toward the equator,and then head eastward along the equator drove by the earth at a．speed of about．250 kilometers per day．When enough Kelvin开尔文波 waves of adequate amplitude （振幅） arrive from the western Pacific,their negative sea-level signal讯号 overcomes the feedback mechanism（反馈机制）,raising the sea level,and they begin to drive the system into the opposite cold mode（模式）．This produces a gradual change in winds,one that will eventually send positive sea-level Rossby waves westward,waves that will eventually return as cold cycle—ending positive Kelvin waves beginning another warming cycle．
谢绝软件翻译

有关求百分比,英语题目
The administration fee for the American Mathematics competition was US4.00dollars for each student. The organiser collected S5.00dollars from each student.If the exchange rate was S1.00dollar=US1.32dollars,calculate the percentage of the amount of money earned or lost by the organiser. 请详细告诉我解法!

英语翻译
The only constant appearing more frequently in mathematics than e is π.
1.到底是谁比谁经常出现
2.另外这句话有语法上的错误没有?

26.With the help of a _______,you can work out the mathematical problem quickly.
A.car
B.plane
C.computer
D.Tv set

请问这道题选什么呢?
This child is a born mathematician.He loves mathematics he will spend a whole day solving mathematical problems without remembering to have meals.
A and so B to the extent that C so much so that D so much that
诶~我觉得我会选B或D,但我不知道B和D在这道题里有什么区别咧.此题来自于大学英语（综合教程）二 test yourself（Units 1—4）.谢谢~~ 我没分给啦.sorry.穷死了
后来我在课本上找到答案，答案是选C。我奔泪............................请问为什么呢？

In order to be a good scientist ,one must understand mathematics.