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问题 单项选择题

有一个内阻为0.15Ω的电流表，最大量程是1A，现将它并联一个0.05Ω的小电阻，则这个电流表量程可扩大为（）。

A、3A

B、4A

C、6A

D、2A

答案

参考答案：B

解答题
设a＞0，b＞0，若矩阵A=
a0
0b
把圆C：x2+y2=1变换为椭圆E：
x2
4
+
y2
3
=1．
（1）求a，b的值；
（2）求矩阵A的逆矩阵A-1．
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填空题

A Great Friendship


Thomas Jefferson and James Madison met in 1776. Could it have been any other year They worked together starting then to further American Revolution and later to shape the new scheme of government. From the work sprang a friendship perhaps incomparable in intimacy and the trustfulness of collaboration and induration. It lasted 50 years. It included pleasure and utility but (1) and above them, there were shared purpose, a common end (2) an enduring goodness on both sides. Four and a half months (3) he died, when he was ailing, debt-ridden, and worried about his impoverished (4) , Jefferson wrote to his longtime friend. His words and Madison’s reply remind us (5) friends are friends until death. They also remind us that (6) a friendship has a bearing on things larger than the (7) itself, for has there ever been a friendship of (8) public consequence than this one
"The friendship which has subsisted (9) us now half a century, the harmony of our political (10) and pursuits have been sources of constant happiness to me through (11) long period. It’s also been a great solace to me to believe that you’re (12) in vindicating to posterity the course that we’ve pursued for preserving to them, (13) all their purity, their blessings of self-government, (14) we had assisted in acquiring for them. If ever the earth has beheld a (15) of administration conducted with a single and steadfast eye to the general (16) and happiness of those committed to it, one (17) , protected by truth, can never known reproach, it is that to which our (18) have been devoted. To myself you have been a pillar of (19) throughout life. Take care of me when dead and be assured that I (20) leave with you my last affections." A week later Madison replied—"You cannot look back to the long period of our private friendship and political harmony with more affecting recollections than I do. If they are a source of pleasure to you, what aren’t they not to be to me We cannot be deprived of the happy consciousness of the pure devotion to the public good with which we discharge the trust committed to us and I indulge a confidence that sufficient evidence will find in its way to another generation to ensure, after we are gone, whatever of justice may be withheld whilst we are here.\
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