已知x,y∈R+,且x+y>2,求证:1+xy与1+yx中至少有一个小于2.

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问题:

已知x,y∈R+,且x+y>2,求证:
1+x
y
1+y
x
中至少有一个小于2.
考点:不等式的定义及性质反证法与放缩法
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汽动给水泵若要隔绝,则给水泵前置泵必须停用。

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由国家资本金、法人资本金和个人资本金形成的股份都为国内投资主体所拥有,简称( )。

A.A股

B.B股

C.C股

D.N股

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There is an ever-widening gap between black male college enrollees and their female and white counterparts, says the American Council on Education (ACE).
Twenty years ago, according to ACE’s "Annual Status Report on Minorities in Higher Education," 30 percent of African American male high school graduates (ages 18 to 24) were enrolled in college, compared with 28 percent of same-age black females and 41 percent of white males.
Now, some 37 percent of black men are enrolled, compared with 42 percent of African American women and 44.5 percent of white males. So while there are more black males enrolling in college today than 20 years ago, other groups have outstripped them in enrolling and, even more importantly, in retention rates.
The graduation rate of black men is lower than that of any group. Only 35 percent of black males enrollees graduated within six years from colleges in 1996, compared with 59 percent of white males, 46 percent of Hispanic men, 41 percent of American Indian males and 45 percent of the black women who entered the same year.
Surveys and reports are hinting that the country’s educational apparatus is stacked against the black male. Fewer than one in five students of color have graduated from high school, have a set of college-prep courses on their high school transcripts and "demonstrate basic literacy" -- the necessities for being "college ready."
Another glaring problem is that black males are disproportionately labeled as discipline and behavioral problems and fast tracked out of high schools through expulsions and suspensions.
As if that’s not enough, says ACE’s William Harvey, there’s a virtual drying up of federal aid-to-education grant money coupled with jacked-up tuitions, which make it necessary for low-income students to assume an average $ 20,000 debt to finish a four-year curriculum.
"For those in the lower economic category, the availability of financial aid determines who gets to go to college and who doesn’t," observes Harvey.
Harvey points out that, over the years, federal funding has undergone a "complete reversal," from "a 70 percent to 30 percent grant-to-loan ratio 20 years ago" to the exact opposite today.
"An 18-year-old male will be more inclined to say, ’I want money in my pocket now’ and attempt to get a job," adds Harvey. "But many take on the debt, become part-time students, work 20-plus hours a week and become five-year students at a four-year college."
The inequity of that educational apparatus is especially clear when you look at the black males who persevere -- those who go on to finish high school, earn a bachelor’s degree and even finish grad school.
A recently released Census report shows that, whether they have a high school diploma or a master’s degree, black men will earn roughly 25 percent less than Whites.

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食物中毒具有以下特征除了()

A.突然暴发,易集体发病

B.临床表现相似,多以胃肠道症状为主

C.人与人之间具有传染性

D.人与人之间无传染性

E.发病者与某种食物有确切的关系

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做人工呼吸时,施救者呼出的CO2对中毒者有影响吗?为什么?

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