单选题设f(x)在点x0处不连续，则( )。

单选题设，其中x≠y且xy＞0．又设则x=0为f(x)的______

单选题三角形周长为7 (1)等腰三角形两边a，b满足|a-b+2|+(2a+3b-11)2=0 (2)直角三角形，三边成等差数列，且内切圆半径为1 A.条件(1)充分，但条件(2)不充分； B.条件(2)充分，但条件(1)不充分； C.条件(1)和(2)单独都不充分，但条件(1)和(2)联合起来充分； D.条件(1)充分，条件(2)也充分； E.条件(1)和(2)单独都不充分，条件(1)和(2)联合起来也不充分。

单选题[此试题无题干]

单选题(A)1(B)∞(C)e-1(D)e

单选题设α1、α2、α3线性无关，则( )也线性无关． A．α1+α2、α2+α3、α3-α1 B．α1+α2、α2+α3、α1+2α2+α3 C．α1+2α2、22α2+3α3、3α3+α1 D．α1+α2+α3、2α1-3α2+22α3、3α1+5α2-5α3

单选题=()．

单选题设函数y=f(x)有二阶导数，对任意实数x，满足：f(x)=-f(-x)及f(x)=f(x+1)，若f'(1)＞0，则有 ( )

单选题下列命题正确的是

单选题设0＜p≤1，级数______。A．绝对收敛B．条件收敛C．发散D．敛散性与P有关

单选题已知2a+b+5c=0，a+2b+4c=0，c≠0，则a:b=( )．

单选题设A，B，C均为n阶矩阵，若AB=C，且B可逆，则______ A．矩阵C的行向量组与矩阵A的行向量组等价． B．矩阵C的列向量组与矩阵A的列向量组等价．　　C．矩阵C的行向量组与矩阵B的行向量组等价．　 D．矩阵C的列向量组与矩阵B的列向量组等价．

单选题 Fried foods have long been frowned upon. Nevertheless, the skillet is about our handiest and most useful piece of kitchen equipment. Stalwart lumberjacks and others engaged in active labor requiring 4,000 calories per day or more will take approximately one-third of their rations prepared in this fashion. Meat, eggs, and French toast cooked in this way are served in millions of homes daily. Apparently the consumers are not beset with more signs of indigestion than afflict those who insist upon broiling, roasting, or boiling. Some years ago one of our most eminent physiologists investigated the digestibility of fried potatoes. He found that the pan variety was more easily broken down for assimilation than when deep fat was employed. The latter, however, dissolved within the alimentary tract more readily than the boiled type. Furthermore, he learned, by watching the progress of the contents of the stomach by means of the fluoroscope, that fat actually accelerated the rate of digestion. Now all this is quite in contrast with "authority". Volumes have been written on nutrition, and everywhere the dictum has been accepted--no fried edibles of any sort for children. A few will go so far as to forbid this style of cooking wholly. Now and then an expert will be bold enough to admit that he uses them himself. The absence of discomfort being explained on the ground that he possesses a powerful gastric apparatus. We can of course sizzle perfectly good articles to death so that they will be leathery and tough. But thorough heating, in the presence of shortening, is not the awful crime that it has been labeled. Such dishes stimulate rather than retard contractions of the gall bladder. Thus it is that bile mixes with the nutriment shortly after it leaves the stomach. We don't need to allow our foodstuffs to become oil-soaked, but other than that, there seems to be no basis for the widely heralded prohibition against this method. But notions become fixed. The first condemnation probably arose because an "oracle" suffered from dyspepsia, which he ascribed to some fried item on the menu. The theory spread. Others agreed with him, and after a time the doctrine became incorporated in our textbooks. The belief is now tradition rather than a proved fact. It should have been refuted long since, as experience has demonstrated its falsity.