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电路如图所示，已知R=20Ω，基波ωL=10/3Ω，，基波1/ωC=60Ω，求电流的i（t）及电感两端电压uL的谐波表达式。

答案

参考答案：

直流分量单独作用时：

三次谐波单独作用时：3ωL=10Ω  

1/3ωC=20Ω

单项选择题 A1型题

当相关系数为0时，则（）

A.两变量不存在任何关系

B.两变量存在相互关系的可能性很小

C.两变量不存在相关关系

D.两变量不存在直线相关关系，但不排除存在某种曲线关系

E.以上均不对
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单项选择题

Like many other aspects of the computer age, Yahoo began as an idea, (1) into a hobby and lately has (2) into a full-time passion. The two developers of Yahoo, David Filo and Jerry Yang, Ph. D candidates (3) Electrical Engineering at Stanford University, started their guide in April 1994 as a way to keep (4) of their personal interest on the Internet. Before long they (5) that their homebrewed lists were becoming too long and (6) . Gradually they began to spend more and more time on Yahoo.

During 1994, they (7) yahoo into a customized database designed to (8) the needs of the thousands of users (9) began to use the service through the closely (10) Internet community. They developed customized software to help them (11) locate, identify and edit material (12) on the Internet. The name Yahoo is (13) to stand for "Yet Another Hierarchical Officious Orale", but Filo and Yang insist they selected the (14) because they considered themselves yahoos. Yahoo itself first (15) on Yang’s workstation, "akebono", while the search engine was (16) on Filo’s computer, "Konishiki".

In early 1995 Marc Andersen, co-founder of Netscape Communication in Mountain View, California, invited Filo and Yang to move their files (17) to larger computers (18) at Netscape. As a result Stanford’s computer network returned to (19) , and both parties benefited. Today, Yahoo (20) organized information on tens of thousands of computers linked to the web.

2（）

A.made

B.saw

C.looked

D.turned
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