/ f /, / v /，/ θ / , / ð /，/ s / , / z / ，/ ʃ / , / ʒ / ，/ h / , / r /的说法正确的是：

试证明，若ψ(x，y．z)连续，则

  

  其中S由x=x(u，v)，y=y(u，v)，z=z(u，v)给出，(u，c)∈Ω．三个函数有连续偏导数，且三个相应雅可比行列式不同时为零．E=x'_u²+y'_u²+z'_u²，F=x'_ux'_v+y'_uy'_v+z'_uz'_v，G=x'_u²+y'_v²+z'_v²

Competitors complain that Microsoft's recent settlement of their antitrust case with the federal government will do little to protect them or consumers from the software giant's monopoly power①. But they hold out hope that state attorney generals could make the deal more restrictive. "My guess is that all Bill Gates could do was to suppress a big grin when he held his press conference this morning," said Mitchell Kertz-man, chief executive of Liberate Technologies, a rival provider of software for interactive TV. "This settle merit does not come close to matching the scope of the violation of antitrust law that Microsoft has been convicted of," he added. "It was an inexplicably bad deal for the government."

Microsoft and the Justice Department presented the settlement to a federal judge Friday, saying that it would end the antitrust case in a way that would help the declining economy. US District Judge Colleen Kol-lar-Kotelly agreed to review it and gave the 18 states involved in the case until Tuesday to decide whether to accept the plan.

Several competitors called on the state attorney generals to insist on making changes to the settlement. Sun Microsystems' general counsel, Michael Morris, said the Justice Department was "walking away from a case they had already won." Paul T. Cappuccio, the general counsel for AOL Time Warner, said the settlement ".does too little to promote competition and protect consumers, and can too easily be evaded by a determined monopolist like Microsoft."

The state attorney generals had been pressing for stiffer penalties, but on Friday several said progress had been made. Among the key elements of the settlement, Microsoft would have to:

—Help rivals make products compatible with the Windows operating system, which runs 91 percent of the world's computers.

—Stop using exclusive deals with computer sellers to put competitors at a disadvantage.

—Let three in-house independent experts monitor its compliance.

"We are quite disappointed. We believe there are a lot of issues that have not been addressed," said Michald Mace, chief officer of handheld computer maker Palm, which makes an operating system that competes with one from Microsoft. Several tech executives said the settlement was too focused on restricting Microsoft's Widows monopoly, and not its broader business practices and non-PC initiatives②.

"This is a reward, not a remedy. It fails to terminate the illegal monopoly and fails to free the market from anti-competitive conduct," said Kelly Jo Macarthur, general counsel for Real Networks, which makes music and video software, threatened by Windows Media Player. "This agreement allows a declared illegal monopolist to determine, at its sole discretion, what goes into the monopoly operating system in the future," she added.

We can infer from the text that the main issue behind Microsoft's antitrust case is the need ______.

A．to restrict the expansion of software companies

B．to limit the reach of Microsoft's Windows operating system

C．to prevent Microsoft from monopolizing the computer software industry

D．to assist its competitors in making products compatible with Windows

A.P=f(Q)

B.Z=f(X，Y，Z)

C.B=f(P，E)

D.T=f(S，V，U)

"It was the beginning of a revolution in America and the world, a revolution that some have yet to acknowledge and many have yet to appreciate," says Harold Skramstad, president of the Henry Ford Museum in Dearborn, Michigan. 1776? No indeed: 1896, when Frank Duryea finally perfected the Duryea Motor, Wagon. At its first airing, the contraption rolled less than 100 metres before the transmission froze up. But by the end of 1896 Duryea had sold 13 of them, thus giving birth to the American motor industry.

That industry (whose roots, outside America, are usually attributed to tinkerings by Messrs Daimler and Benz in Germany) is being celebrated hugely over the coming months, culminating with a Great American Crnise-in in Detroit in June. "Our goal is to attract the greatest collection of antique and classic cars this nation has ever seen in one place at one time," says Mr Skramstad modestly.

Americans may indeed blame the car for almost everything that has happened to their country, and themselves, since 1896. The car has determined.

The way they live. From cradle to grave, the car marks every rite of American passage. Home by car from the maternity ward; first driving licence (usually at the age of 16); first (backseat) sexual experience; first car of one's own (and the make of car is a prime determinant of social status, symbolic of everything a person is or does). In Las Vegas, and elsewhere, Americans can get married at drive-in chapels. They then buy, or lust after, a house with garages big enough for not one but two or three cars. This allocates more space to cars than to children. And when the time comes, they may lie in state at a drive-through funeral home, where you can pay your respects without pulling over.

The way they shop. Main Street has been replaced by the strip mall and the shopping mall, concentrating consumer goods in an auto-friendly space. A large part of each shopping trip must now be spent, bags under chin, searching for the place where the car was left. (And another point: bags have annoyingly lost their carrying handles since shoppers ceased to be pedestrian) Since car-friendly living and shopping became the role, most built-up parts of America now look like every other part. There is simply no difference between a Burger Inn in California and one on the outskirts of Boston.

The way they eat. A significant proportion of Americans' weekly meals are now consumed inside cars, sometimes while parked outside the (drive-by) eatery concerned, sometimes en route, which leads to painful spillages in laps, leading to overburdening of. The legal system. Dozens of laws have been written to deal with car cases, ranging from traffic disputes to product liability. Drive-by shootings require a car, as do most getaways. The car is a great crime accessory; and it also causes the deaths of nearly 40,000 Americans every year.

Personal finances. Before the age of the car, few people went into debt; no need to borrow money to buy a horse. Now Americans tie themselves up with extended installment loans, and this in turn has spawned a whole financial industry.

The wealth of the nation. By 1908, an estimated 485 different manufacturers were building cars in the United States. Employment grew nearly 100-fold in the industry during the first decade of the 20th century. When Henry Ford, in a stroke of genius, automated his production line he required a rush of new, unskilled labour, which he enticed by offering an unheard-of ＄5 a day in wages. Henceforth, workers could actually afford to buy what they built.

And Americans never looked back. Today, the Big Three car manufacturers (Food, GM and Chrysler) generate more than ＄200 billion a year in business inside the United States. Directly and indirectly, the industry employs roughly one in seven workers. Every car job is reckoned to add ＄100,000 in goods and services to the economy, twice the national a

A．introduce new models of automobiles

B．emphasize automobiles have brought wealth to the nation

C．commemorate the centenary anniversary of the birth of the American motor industry

D．illustrate the rapid development of automobile industry in America

The first big-name hackers include Steve Wozniak, Bill Gates and Linus Torvalds, all now highly recognisable names behind many of the computer technologies used today. These early hackers had a love of technology and a compelling need to know how it all worked, and their goal was to push programs beyond what they were designed to do. Back then, the word "hacker" didn't have the negative connotation it has today. The original hacker ethic, rooted out of simple curiosity and a need to be challenged, appears to be dead.

The objectives of early hackers are a far cry from the goals of today's hacker. The motivation of the new breed of hackers appears not to be curiosity, or a hunger for knowledge, as it used to be. Instead, most of today's hackers are driven by greed, power, revenge, or some other malicious intent, treating hacking as a game or sport, employing the tools that are readily available via the Internet.

The rate of security attacks is actually outpacing the growth of the Internet. This means that something besides the growth of the Internet is driving the rise in security attacks. Here are some realities you should know about: Operating systems and applications will never be secure. New vulnerabilities will be introduced into your environment every day. And even if you ever do get one operating system secure, there will be new operating systems with new vulnerabilities—phones, wireless devices, and network appliances. Employees will never keep up with security polices and awareness. It doesn't matter how much you train and educate your employees. If your employees disregard warnings about the hazards of opening questionable email attachments, how are you going to educate them about properly configuring firewalls and intrusion detection systems for their PCs? Managers have more responsibility than ever. And on top of the realities listed above, security managers are being asked to support increasing degrees of network availability and access.

There are some good security measures you can take: Employ a layer 7, full-inspection firewall. Automatically update your anti-virus at the gateway, server and client. Keep all of your systems and applications updated. Hackers commonly break into a Web site through known security holes, so make sure your servers and applications are patched and up to date. Turn off unnecessary network services. Eliminate all unneeded programs. Scan network for common backdoor services—Use intrusion detection systems, vulnerability scans, anti-virus protection.

Which of the following statements of Steve Wozniak, Bill Gates and Linus Torvalds is TRUE?

A．They are all good examples of today's computer users.

B．They are driven by greed, power, revenge, or some other malicious intent.

C．Their goal is to push programs beyond what they are designed to do.

D．They are all dead.

The first big-name hackers include Steve Wozniak, Bill Gates and Linus Torvalds, all now highly recognisable names behind many of the computer technologies used today. These early hackers had a love of technology and a compelling need to know how it all worked, and their goal was to push programs beyond what they were designed to do. Back then, the word "hacker" didn't have the negative connotation it has today. The original backer ethic, rooted out of simple curiosity and a need to be challenged, appears to be dead.

The objectives of early hackers are a far cry from the goals of today's hacker. The motivation of the new breed of hackers appears not to be curiosity, or a hunger for knowledge, as it used to be. Instead, most of today's hackers are driven by greed, power, revenge, or some other malicious intent, treating hacking as a game or sport, employing the tools that are readily available via the Internet.

The rate of security attacks is actually outpacing the growth of the Internet. This means that something besides the growth of the Internet is driving the rise in security attacks. Here are some realities you should know about: Operating systems and applications will never be secure. New vulnerabilities will-be introduced into your environment every day. Even if you ever do get one operating system secure, there will be new operating systems with new vulnerabilities—phones, wireless devices, and network appliances. Employees will never keep up with security polices and awareness. It doesn't matter how much you train and educate your employees. If your employees disregard warnings about the hazards of opening questionable email attachments, how are you going to educate them about properly configuring firewalls and intrusion detection systems for their PCs? Managers have more responsibility than ever. And on top of the realities listed above, security managers are being asked to support increasing degrees of network availability and access. There are some good security measures you can take: Employ a layer 7, full-inspection firewall. Automatically update your anti-virus at the gateway, server and client. Keep all of your systems and applications updated. Hackers commonly break into a Web site through known security holes, so make sure your servers and applications are patched and up to date. Turn off unnecessary network services. Eliminate all unneeded programs. Scan your network for common backdoor services, and use intrusion detection systems, vulnerability scans, and anti-virus protection.

Which of the following statements of Steve Wozniak, Bill Gates and Linus Torvalds is TRUE?

A．They were all good examples of today's computer users.

B．They were driven by greed, power, revenge, or some other malicious intent.

C．Their goal was to push programs beyond what they are designed to do.

D．They are all dead.

The first big-name hackers include Steve Wozniak, Bill Gates and Linus Torvalds, all now highly recognizable names behind many of the computer technologies used today. These early hackers had a love of technology and a compelling need to know how it all worked, and their goal was to push programs beyond what they were designed to do. Back then, the word "hacker" didn't have the negative connotation it has today. The original hacker ethic, rooted out of simple curiosity and a need to be challenged, appears to be dead.

The objectives of early hackers are a far cry from the goals of today's hacker. The motivation of the new breed of hackers appears not to be curiosity, or a hunger for knowledge, as it used to be. Instead, most of today's hackers are driven by greed, power, revenge, or some other malicious intent, treating hacking as a game or sport, employing the tools that are readily available via the Internet.

The rate of security attacks is actually outpacing the growth of the Internet. This means that something besides the growth of the Internet is driving the rise in security attacks. Here are some realities you should know about: Operating systems and applications will never be secure. New vulnerabilities will be introduced into your environment every day. And even if you ever do get one operating system secure, there will be new operating systems with new vulnerabilities—phones, wireless devices, and network appliances. Employees will never keep up with security polices and awareness. It doesn't matter how much you train and educate your employees. If your employees disregard warnings about the hazards of opening questionable email attachments, how are you going to educate them about properly configuring firewalls and intrusion detection systems for their PCs? Managers have more responsibility than ever. And on top of the realities listed above, security managers are being asked to support increasing degrees of network availability and access.

There are some good security measures you can take: Employ a layer 7, full-inspection firewall. Automatically update your anti-virus at the gateway, server and client. Keep all of your systems and applications updated. Hackers commonly break into a Web site through known security holes, so make sure your servers and applications are patched and up to date. Turn off unnecessary network services. Eliminate all unneeded programs. Scan network for common backdoor services—Use intrusion detection systems, vulnerability scans, anti virus protection.

Which of the following statements of Steve Wozniak, Bill Gates and Linus Torvalds is TRUE?

A．They are all good examples of today's computer users.

B．They are driven by greed, power, revenge, or some other malicious intent.

C．Their goal is to push programs beyond what they are designed to do.

D．They are all dead.