问答题求曲线段y=x 2 (0≤x≤1)上一点处的切线，使该切线与直线y=0，x=1和曲线y=x 2 所围成图形的面积最小．

问答题{{B}}Directions:{{/B}} Read the following text carefully and then translate the underlined segments into Chinese. Write your pieces of Chinese version in the proper space on your Answer Sheet Ⅱ. It is astonishing how little is known about the working of the mind. But however little or much is known, it is fairly clear that the model of the logic-machine is not only wrong but mischievous. There are people who profess to believe that man can live by logic alone. If only they say, men developed their reason, looked at all situations and dilemmas logically, and proceeded to devise rational solutions, all human problems would be solved. Be reasonable. Think logically. Act rationally. This line of thought is very persuasive, not to say seductive. 1) {{U}}It is astonishing, however, how frequently the people most fanatically devoted to logic and reason, to a cold review of the "facts" and a calculated construction of the truth, turn out not only to be terribly emotional in argumentation, but obstinate before any "truth" is "proved"{{/U}} -- deeply committed to emotional positions that prove rock-resistible to the most massive accumulation of unsympathetic facts and proofs. 2) {{U}}If man's mind cannot be turned into a logic-machine, neither can it function properly as a great emotional sponge, to be squeezed at will.{{/U}} All of us have known people who gush as a general response to life - who gush in seeing a sunset, who gush in reading a book, who gush in meeting a friend. They may seem to live by emotion alone, but their constant gushing is a disguise for absence of genuine feeling, a torrent rushing to fill a vacuum. It is not uncommon to find beneath the gush a cold, analytic mind that is astonishing in its meticulousness and ruthless in its calculation. Somewhere between machine and sponge lies the reality of the mind - a blend of reason and emotion, of actuality and imagination, of fact and feeling. 3) {{U}}The entanglement is so complete, the mixture so thoroughly mixed, that it is probably impossible to achieve pure reason or pure emotion, at least for any sustained period of time.{{/U}} 4) {{U}}It is probably best to assume that all our reasoning is fused with our emotional commitments and beliefs, all our thoughts colored by feelings that lie deep within our psyches.{{/U}} Moreover, it is probably best to assume that this stream of emotion is not a poison, not even a taint, but is a positive life-source, a stream of psychic energy that animates and vitalizes our entire thought process. 5) {{U}}The roots of reason are embedded in feelings - feelings that have formed and accumulated and developed over a lifetime of personality-shaping.{{/U}} These feelings are not for occasional using but are inescapable. To know what we think, we must know how we feel. It is feeling that shapes belief and forms opinion. It is feeling that directs the strategy of argument. It is our feelings, then, with which we must come to honorable terms.

问答题已知ξ=[1，1，-1]T是矩阵的一个特征向量．

问答题设z=f(x2+y2)，其中f具有二阶导数，求

问答题若，求k的值．

问答题求

问答题设X和Y是两个相互独立的随机变量，且均服从(-b，b)上的均匀分布。 (Ⅰ)求X和Y的联合概率密度。 (Ⅱ)求t的二次方程t2+Xt+Y=0有实根的概率。

问答题有10张签，其中有6张电影票，10人轮流抽签，求第二个人抽到电影票的概率是多少?

问答题设(1)求du；(2)求