填空题设a＞0，则I=

填空题设的敛散性为________．

填空题点(4，5)关于直线y=x的对称点的坐标为________．

填空题二元函数z=x2+3xy+y2+2x，则

填空题设函数z=sin(x+2y),则z/x=

填空题In the following text, some sentences have been removed. For Questions (41-45), choose the most suitable one from the list A-G to fit into each of the numbered blank. There are two extra choices, which do not fit in any of the gaps. English has become the world's number one language in the 20th century. In every country where English is not the native language, especially in the Third World, people must strive to learn it to the best of their abilities, if they want to participate fully in the development of their countries. 41．______ A close examination reveals a great number of languages have fallen casualty to English. For example, it has wiped out Hawaiian, Welsh, Scotch Gaelic, Irish, native American languages, and many others. Luckily, some of these languages are now being revived, such as Hawaiian and Welsh, and these languages will live again, hopefully, if dedicated people continue their work of reviving them. 42．______If this situation continues, the native or official languages of these countries will certainly die within two or three generations. This phenomenon has been called linguistic genocide. A language dies if it is not fully used in most activities, particularly as a medium of instruction in schools. 43．______According to many studies, only around 20 to 25 percent of students in these countries can manage to learn the language of instruction (English) as well as basic subjects at the same time. Many leaders of these Third World countries are obsessed with English and for them English is everything. They seem to believe that if the students speak English, they are already knowledgeable. These leaders speak and write English much better than their national languages. If these leaders deliver speeches anywhere in the world they use English and they feel more at home with it and proud of their ability as well. The citizens of their countries do not understand their leaders' speeches because they are made in a foreign language. All the greatest countries of the world are great because they constantly use their own languages in all national development activities, including education. From a psychological point of view, those who are taught in their own language from the start will develop better self-confidence and self-reliance. From a linguistic point of view, the best brains can only be produced if students are educated in their own language from the start. 44. There is nothing wrong, however, in learning a foreign language at advanced levels of education. 45. [A] But many people are concerned that English's dominance will destroy native languages. [B] But the best thing to do is to have a good education in one's native language first, then go abroad to have a university education in a foreign language. [C] Suppose you work in a big firm and find English very important for your job because you often deal with foreign businessmen. Now you are looking for a place where you can improve your English, especially your spoken English. [D] Nonetheless, a world full of different languages will disappear if the present trend in many countries to use English to replace the national or official languages in education, trade and even politics continues. [E] Those who are taught in a foreign language from the start will tend to be imitators and lack self-confidence. They will tend to rely on foreign consultants. [F] Here are some advertisements about English language training from newspapers. You may find the information you need. [G] The Third World countries that are now using English as a medium of instruction are depriving 75 percent of their future leaders of a proper education.

填空题微分方程yy"+y"2=0满足初始条件y|x=0=1，的特解是________．

填空题∫e+∞

填空题方程满足f(0)=0的特解为______。

填空题设f(x)=，则f(n)(x)=________．

填空题设3阶矩阵A的特征值为1，2，2，E为3阶单位矩阵，则｜4A －1 －E｜=____________．

填空题设，则A-1=________．

填空题从n阶行列式的展开式中任取一项，此项不含a11的概率为，则n=________．

填空题极限________．

填空题函数f(x)=lnarcsinx的连续区间是______.

填空题设则与直线2x+y=1垂直的曲线y(x)的切线方程为________．

填空题设方程组无解，则a=________．

填空题买来蘑菇10kg，含水量为90%，晾晒一会儿后，含水量为87.5%．(1)每小时蒸发1kg的水分，晾晒了2h；(2)每小时蒸发kg的水分，晾晒了2h．

填空题已知f"(sinx)=cos 2 x，则f(x)=______