单选题设f(x)在x=0处3阶可导，且f'(0)=0，f"(0)=0，f"'(x)＞0，则______． A．x=0是f(x)的极小值点 B．x=0是f(x)的极大值点 C．在点(0，f(0))的左、右邻域曲线y=f(x)分别为凹与凸 D．在点(0，f(0))的左、右邻域曲线y=f(x)分别为凸与凹

单选题已知f(x)具有二阶连续导数，g(x)为连续函数，且则()

单选题设f(x)与g(x)分别为定义在(-∞，+∞)上的严格增函数与严格减函数，则 A.f(g(x))为严格减函数． B.f(g(x))为严格增函数． C.f(x)g(x)为严格减函数． D.f(x)g(x)为严格增函数．

单选题A是n阶方阵，A * 是A的伴随矩阵，则|A * |=______

单选题With a series of well-timed deals, private-equity firms are giving traditional media- managers cause to be envious. The Warner Music transaction, in which Edgar Bronfman junior and three private-equity firms paid Time Warner $ 2.6 billion for the unit in 2003, is already judged a financial triumph for the buyers. Their success is likely to draw still more private-equity into the industry. And the investments are likely to get bigger: individual private-equity funds are growing--a $10 billion fund is likely this year--so even the biggest media firms could come within range, especially if private-equity investors club together. Some private-equity firms have long put money in media assets, but mostly reliable, relatively obscure businesses with stable cash flows. Now, some of them are placing big strategic bets on the more volatile bits, such as music and movies. And they are currently far more confident than the media old guard that the advertising cycle is about to turn sharply upwards. One reason why private-equity is making its presence felt in media is that it has a lot of money to invest. Other industries are feeling its weight too. But private-equity's buying spree (狂购乱买) reveals a lot about the media business in particular. Media conglomerates( 联合公司) lack the confidence to make big acquisitions, after the last wave of deals went wrong. Executives at Time Warner, for instance, which disastrously merged with AOL in 2000, wanted to buy MGM, a movie studio, but the board (it is said) were too nervous. Instead, private- equity firms combined with Sony, a consumer-electronics giant, to buy MGM late last year. Private-equity's interest also reflects the fact that revenue growth in media businesses such as broadcast TV and radio is now hard to come by. The average annual growth rate for 12 categories of established American media businesses in 1998-2003, excluding the internet, was just 3.4% , says Veronis Suhler Stevenson, an investment bank. Private-equity puts a higher value on low-growth, high cashflow assets than the public stockmarket, says Jonathan Nelson, founder of Providence Equity Partners, a media-focused private-equity firm. What private-equity men now bring to the media business, they like to think, is financial discipline plus an enthusiastic attitude towards new technology. Old-style media managers, claim the newcomers, are still in denial about how technology is transforming their industry. Traditional media managers grudgingly agree that, so far, private-equity investors are doing very nicely indeed from their entertainment deals. The buyers of Warner Music have already got back most of their $ 2.6 billion from the firm by cutting costs, issuing debt and making special payouts to shareholders. This year, its investors are expected to launch an initial public offering, which could bring them hundreds of millions more.

单选题设3阶矩阵A的特征值互不相同，若行列式|A|=0，则A的秩为______．

单选题若正项级数收敛，则

单选题设f(x)具有二阶连续导数，f(0)=0，f'(0)=0，f"(x)≠0．并且在曲线y=f(x)上任意一点(x，f(x))(x≠0)作此曲线的切线，此切线在x轴上的截距为u，则=A．．B．1．C．．D．2．

单选题设随机变量X，Y相互独立，且X～N(0，1)，Y～N(1，1)，则______．A．P(X+Y≤0)=B．P(X+Y≤1)=C．P(X-Y≤0)=D．P(X-Y≤1)=