eachxother哪里的品牌，已知fxlnx1gx12ax2bx1若b2且hxfx1gx存在单调

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1，已知fxlnx1gx12ax2bx1若b2且hxfx1gx存在单调
2，最新好听的歌曲
3，天文的文意思是什么

1，已知fxlnx1gx12ax2bx1若b2且hxfx1gx存在单调

解：（i），则因为函数h(x)存在单调递减区间，所以<0有解.又因为x>0时，则ax2+2x－1>0有x>0的解.①当a>0时，y=ax2+2x－1为开口向上的抛物线，ax2+2x－1>0总有x>0的解；②当a<0时，y=ax2+2x－1为开口向下的抛物线，而ax2+2x－1>0总有x>0的解；则△=4+4a>0,且方程ax2+2x－1=0至少有一正根.此时，－1<a<0. 综上所述，a的取值范围为（－1，0）∪（0，+∞）.

已知fxlnx1gx12ax2bx1若b2且hxfx1gx存在单调

2，最新好听的歌曲

t天使的翅膀那一年那一夜当我孤单的时候还可以抱着你

2009年好听的歌谢安琪---年度之歌卫兰-----就算世界没童话梁咏琪---错过，爱得起陈奕迅---歌颂，七百年后，不要说话梁静茹---三寸日光，没有如果周丽淇---还是让你走张敬轩---未来的回忆蔡依林---大丈夫，耍大牌方力申---最后的时光丁当-----长大卫兰，黎明---你懂我的爱金莎------这种爱蔡卓妍-----二缺一阿沁-----I believe 容祖儿----搜神记 SS501的歌

【忧伤还是快乐】【一个深爱的女孩】一个字：好。两个字：好听。三个字：很好听。四个字：好听极了。真的！绝不忽悠你。（歌不需要多，只要好听就行了）。希望你能喜欢！能和你一起分享就是一种享受！(*^__^*) 嘻嘻……（楼主喜欢纯音乐吗？在小女的空间里的音乐收藏有很多情感的纯音乐，随时欢迎爱好音乐的你。QQ：1092818191）（如果有需要的，小女会尽力邦楼主找各种各样的歌，听过才推荐给楼主的）!！

放开吧 - 郑凡等不到最爱的人 - 岳明分开后的关心 - 邓紫棋初吻 - 小瑞再说我爱你 - 张志政如果爱好好爱 - 李俊旭倔强爱情的胜利 - 陈绮贞

1994-11-01 你把我灌醉黄大炜 1990-01-01 不只是朋友黄小琥 1996-01 堕落王菲 2000 执迷不悔王菲 2003-09-01 看透莫文蔚 1999-09 静止杨乃文

3，天文的文意思是什么

应该是辞典释义的第六条：自然界的某些现象。同样可以推论，“天文”、“地理”两个对仗的词，同后者中的“理”，这个字作为“自然现象”解，还是比较普遍的，又如“物理”。1．事物错综复杂所造成的纹理或形象：灿若～锦。2．刺画花纹：～身。3．记录语言的符号：～字；～盲；以～害辞。

帮您找了两篇有关天文的科普文，希望对您有所帮助：black holes(黑洞)black holes are some of the strangest things in space. a black hole sucks in anything that gets near it. nothing can escape from a black hole—not even light.black holes are strongnothing escapes from a black hole because its gravity is so strong. gravity is a force that pulls one thing to another. gravity is the force that holds you down on earth. when you jump up, earths gravity pulls you right back down. earths gravity also makes the moon orbit (go around) earth.the more matter (stuff) that is packed in a star, planet, moon, or other object, the stronger is its gravity. gravity makes an object with more matter pull an object with less matter toward it. the sun has a lot more matter than earth. the suns gravity pulls on earth. it makes earth orbit the sun.matter is packed very tightly in some things and loosely in others. the matter that makes up an iron ball is packed much tighter than the matter that makes up a bag of feathers. a scientist would say that an iron ball is much denser than a bag of feathers.a black hole is denser than anything you could imagine. a black hole could have a million times more stuff than our sun. all of this stuff would be packed into an area smaller than a city. the force of gravity from so much stuff packed into such a small area is awesome.where do black holes come from?astronomers and physicists think black holes come from dying stars. a dying star burns out and stops shining. all the stuff that makes up the star starts falling in on itself. the star gets denser and denser. if the star is big enough and has enough matter, it could get dense enough to become a black hole.studying black holesno one has really seen a black hole. you cannot see black holes because they do not give off any kind of light. physicists used math to predict that black holes exist.astronomers look for signs of black holes. astronomers study powerful rays coming from stars in deep space. the stars seem to be orbiting black holes. astronomers think that black holes are sucking gas from the stars, and this makes the stars give off x rays.galaxies are enormous groups of stars. astronomers think that most galaxies have huge black holes at their centers. the hubble space telescope took pictures of a disk of hot gases at the center of our own milky way galaxy. astronomers think this disk is going around an enormous black hole right in the center of our galaxy.big bang(宇宙大爆炸)the universe contains everything that exists: earth, the sun, the stars, galaxies (collections of billions of stars), and everything else in space. people have wondered how the universe got started for thousands of years. most scientists now think they have the answer. they think the universe began about 14 billion years ago with a kind of big explosion. they call the explosion the big bang.what happened after the big bang?no one knows what caused the big bang, but scientists think they know what happened all the way back to the first seconds after the big bang.the brand new universe was very hot and very small. it blew outwards very fast. in the first three minutes, matter started to form. hundreds of years later, the universe looked like a big ball of fire.you can picture the universe as something like a black balloon with white dots painted on it. the black represents space and the white dots are galaxies. blowing air into the balloon makes it bigger. the spaces between each dot get farther apart as the balloon expands.as it got bigger, the universe got cooler. hydrogen gas formed. the gas broke into clumps. the clumps came together to make galaxies and stars. other kinds of matter formed in the stars. finally, planets like earth formed around some stars.is there proof of a big bang?the expansion of the universe is evidence for the big bang. american scientist edwin hubble studied light coming from galaxies far out in the universe. in 1929, he found that the galaxies were speeding away from earth and from each other in all directions. scientists tracked the paths of the galaxies back to their starting place. they saw that all the galaxies must have started from the same place. packing all that matter into a small area would make a very dense, searing hot ball—the big bang.scientists use math to describe how the universe behaves. in the early 1900s, german american scientist albert einstein came up with equations that predict an expanding universe. these equations have correctly predicted the motions of stars, planets, and light. more proof came in the 1990s from a spacecraft called the cosmic background explorer (cobe). cobe saw rays coming from far off in the universe. the rays are left over from the early days of the universe. they could only have been created in a much smaller and hotter universe long ago.will the universe keep expanding?scientists are not sure what will happen to the universe. they currently think it will keep expanding forever. they even think the expansion is speeding up. but scientists are still studying this question.

天文的文意思是什么