组卷网>知识点选题>二次不等式能成立问题
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1 . 已知eqId89f2e4143de24e1d8f2a135fb32ea7ef.以下四个命题:
①对任意实数eqIda9cd3f94eb8045438f75e9daccfa7200,存在eqId4d2187284c5d4de29906363f7d21f60f,使得eqIdac121730997d49c1b6e9356c505f15d1
②对任意eqId4d2187284c5d4de29906363f7d21f60f,存在实数eqIda9cd3f94eb8045438f75e9daccfa7200,使得eqIdac121730997d49c1b6e9356c505f15d1
③对任意实数eqId4d2187284c5d4de29906363f7d21f60feqIda9cd3f94eb8045438f75e9daccfa7200,均有eqIdac121730997d49c1b6e9356c505f15d1成立;
④对任意实数eqId4d2187284c5d4de29906363f7d21f60feqIda9cd3f94eb8045438f75e9daccfa7200,均有eqId0836c1003605494a89734a73b75e144c成立.
其中所有正确的命题是(   )
A.①②B.②③C.①③D.②④
解答题 | 较易(0.85) |
2 . 已知函数fx)=x2﹣3mx+nm>0)的两个零点分别为1和2.
(1)求mn的值;
(2)若不等式fx)﹣k>0在x∈[0,5]恒成立,求k的取值范围.
(3)令g(x)=eqId79e05d46621b494da308715d7d43a790,若函数Fx)=g(2x)﹣r2xx∈[﹣1,1]上有零点,求实数r的取值范围.
更新:2021/04/24组卷:655
3 . 已知函数eqId34089f71e4d04f1686fe19764c4a230feqIdfeae73ee3f3e49f09b246bebb55d1101.
(1)若存在eqId37fd7132b8454973bca9e77e73b2fe56,使eqId502640d344474fdd8c352a93a2d27165成立,求实数eqId4d2187284c5d4de29906363f7d21f60f的取值范围;
(2)若对任意eqIdcb00d39f27714ab797bd49d1b3dc2cd1,存在eqId1602c78a049c4812879d3beb46a3c001,都有eqId5a8e0edbecdc46d29c51688eb288ea44成立,求实数eqId4d2187284c5d4de29906363f7d21f60f的取值范围.
解答题 | 一般(0.65) |
4 . 设函数eqId9166a4fde912404db08c6e08dee0ab6f
(1)若eqIde133a99d025341259eab2a276a9c1ff1是偶函数,求k的值
(2)若存在eqId5ac52a25778d4fdaaaf39d30521d8b73,使得eqIdadfde34878c1481b822c4aba64c3712e成立,求实数m的取值范围;
(3)设函数eqId361b6d19b4984b32b5bce8823ebc7910eqIdd077167f12154199a0f30bcefb739eb5eqId10b6934c4906486697a9a648c15332f9有零点,求实数eqId5f420ef2d0b94c4b8a5d8e20a5d1ce2c的取值范围.
更新:2021/04/02组卷:349
5 . 已知函数eqIdab0dd38f9b374cfe883eda24f802a5afeqId9f4b42282cf64402859922e618295b08
(1)判断eqId4837c94ef0ff4dcf9b1dda4df363275aeqIddca4c31f92e1447fb6eceb9fdf294175上的单调性,并利用单调性的定义加以证明;
(2)若不等式eqId797f51436b4e4800a7bb328e5375b95a对任意实数eqId85eb53575dd34c888bbb489e15f1b57e恒成立,求实数eqIda4be99d332154d13a4a6ed1ff6444fe7的取值范围;
(3)若存在eqIddb2434488713493c848a36c620dcdcaf,使得eqId7acf75e902e44235b14231b3bbb3f60b,求实数eqId69f56ef2c88b4b73a560da59f5247a82的取值范围.
解答题 | 一般(0.65) |
6 . 设函数eqIde6f8c86f43be4a9f80ea0d423e3a1eb5
(1)若对任意eqIdf55410feac434626ab025684aec1ff3c,不等式eqIdac121730997d49c1b6e9356c505f15d1恒成立,求实数eqIda4be99d332154d13a4a6ed1ff6444fe7的取值范围
(2)若存在eqIdf55410feac434626ab025684aec1ff3c,不等式eqIdac121730997d49c1b6e9356c505f15d1成立,求实数eqIda4be99d332154d13a4a6ed1ff6444fe7的取值范围
更新:2021/03/12组卷:314
解答题 | 一般(0.65) |
7 . 已知函数eqIdcc64bd9343ec42f88bf096fec4f5f2fa,设eqId8164502d09d44990ac4f2f73ea67e37a,若存在eqId63609c9312b548f4943109e23f2e296d,使eqId5829b31b471b4f1b85cb91d760ba0e85,求eqIdaea992e70d4943e49e893817eb885ed7的取值范围.
更新:2021/03/12组卷:66
9 . 已知函数eqIdeb1cdcbcf6994610b882eafbe7b8ff97eqId786d91b01de541048929eeac9104b754eqIde7533d624c694004b9b9f7b122312dde
(1)求eqId28c4c21271884dfeac29ce0222782376eqId3a124bfa8f874e469f20bf891e29303e的解析式.
(2)若存在eqId821455aeae9b4f0b9dcf8bfc4b54b4ef,使得不等式eqId1d3887ebbc3a4f56ac53ff9e13138273成立,求实数eqIda4be99d332154d13a4a6ed1ff6444fe7的取值范围.
解答题 | 一般(0.65) | 2021·安徽滁州市·高三月考(理)
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10 . 已知函数eqId0f1eaeae83384efabf505c107c67e786在区间eqIdf173839cbdf549429066610d1a327f06上有最小值1和最大值eqId16fc2c4ac7e940cdad49c4a01d735579,设eqId2a35e7da55b6479c96ea737e1b3e1a64.
(1)求ab的值.
(2)若不等式eqId755bf89bbb3e47d5aa6eb51a82f87395eqId79442dcac7014b1e80b9dd41cb4ba0fa上有解,求实数k的取值范围.
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