设函数y=f(x)的定义域为I,如果存在实数M满足:①对于任意实数x∈I,都有f(x)≤M,②存在

\u5b9a\u4e49\u51fd\u6570y=f\uff08x\uff09\uff1a\u5bf9\u4e8e\u4efb\u610f\u6574\u6570m\uff0c\u5f53\u5b9e\u6570x\u2208(m?12\uff0cm+12)\u65f6\uff0c\u6709f\uff08x\uff09=m\uff0e\uff08\u2160\uff09\u8bbe\u51fd\u6570\u7684\u5b9a\u4e49\u57df\u4e3aD\uff0c\u753b

\uff08I\uff09\u5f53x\u2208[0\uff0c12\uff09\u65f6\uff0cf\uff08x\uff09=0\uff0c\u5f53x\u2208[12\uff0c32\uff09\u65f6\uff0cf\uff08x\uff09=1\uff0c\u5f53x\u2208[32\uff0c52\uff09\u65f6\uff0cf\uff08x\uff09=2\uff0c\u5f53x\u2208[52\uff0c72\uff09\u65f6\uff0cf\uff08x\uff09=3\uff0c\u5f53x\u2208[52\uff0c4]\u65f6\uff0cf\uff08x\uff09=4\uff0c\u2234\u56fe\u8c61\u5982\u56fe\u6240\u793a\uff0c\uff08II\uff09\u7531\u4e8ean\uff1d2+10?(25)n\uff0c\u6240\u4ee5f(an)\uff1d6\uff0cn\uff1d14\uff0cn\uff1d23\uff0cn\uff1d32\uff0cn\u22654\uff0c\u56e0\u6b64Sn\uff1d6\uff0cn\uff1d110\uff0cn\uff1d22n+7\uff0cn\u22653\uff1b\uff08III\uff09\u7531f\uff08b1\uff09+f\uff08b2\uff09+f\uff08b3\uff09=4\uff0c\u4e14b1=1\uff0c\u5f97f\uff08q\uff09+f\uff08q2\uff09=3\uff0c\u5f530\uff1cq\u22641\u65f6\uff0c\u5219q2\u2264q\u22641\uff0c\u6240\u4ee5f\uff08q2\uff09\u2264f\uff08q\uff09\u2264f\uff081\uff09=1\uff0c\u5219f\uff08q\uff09+f\uff08q2\uff09\u22642\uff1c3\uff0c\u4e0d\u5408\u9898\u610f\uff1b\u5f53q\uff1e1\u65f6\uff0c\u5219q2\uff1eq\uff1e1\uff0c\u6240\u4ee5f\uff08q2\uff09\u2265f\uff08q\uff09\u2265f\uff081\uff09=1\uff0e\u53c8f\uff08q\uff09+f\uff08q2\uff09=3\uff0c\u2234\u53ea\u53ef\u80fd\u662f<div style="background-image: url(http://hiphotos.baidu.com/zhidao/pic/item/50da81cb39dbb6fd0ba3af920a24ab18962b378d.jpg); background-attachment: initial; background-origin: initial; background-clip: initial; background-color: initial; width: 9px; overflow-x: hidden; overflow-y:

y=f\uff08x\uff09\u7684\u6700\u5c0f\u503c\u7684\u5b9a\u4e49\u662f\u8fd9\u6837\u7684\uff1a
\u8bbe\u51fd\u6570y=f\uff08x\uff09\u7684\u5b9a\u4e49\u57df\u4e3aI\uff0c\u5982\u679c\u5b58\u5728\u5b9e\u6570M\u6ee1\u8db3\uff1a\u2460\u5bf9\u4e8e\u4efb\u610f\u5b9e\u6570x\u2208I\uff0c\u90fd\u6709f(x)\u2265M\uff0c\u2461\u5b58\u5728x0\u2208I\u3002\u4f7f\u5f97f (x0)=M\uff0c\u90a3\u4e48\uff0c\u6211\u4eec\u79f0\u5b9e\u6570M \u662f\u51fd\u6570y=f(x)\u7684\u6700\u5c0f\u503c\u3002

\u4e5f\u5c31\u662f\u8bf4,\u5bf9\u4efb\u610fx\u2208I,\u5b58\u5728x0\u2208I,,\u4f7ff(x)\u2265f\uff08x0)=M

因为条件1只是满足f(x)≤M所以,在1条件下的f(x)的取值完全可以不等于M,条件2是限定了在范围I中必有一个取值使函数值为M

你想的太简单了

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