已知函数 的定义域为 ,则函数 的定义域为( ) A. B. C. D
已知函数的定义域为,则函数的定义域为()A.B.C.D....
已知函数 的定义域为 ,则函数 的定义域为( ) A. B. C. D.
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小柒wqft
2014-10-07
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试题分析:根据题意,由于函数 ![](https://iknow-pic.cdn.bcebos.com/b219ebc4b74543a96c9cc27f1d178a82b80114f9?x-bce-process=image%2Fresize%2Cm_lfit%2Cw_600%2Ch_800%2Climit_1%2Fquality%2Cq_85%2Fformat%2Cf_auto) 的定义域为 ![](https://iknow-pic.cdn.bcebos.com/94cad1c8a786c917d4b46a8aca3d70cf3ac757c9?x-bce-process=image%2Fresize%2Cm_lfit%2Cw_600%2Ch_800%2Climit_1%2Fquality%2Cq_85%2Fformat%2Cf_auto) ,那么可知f(2x)的定义域为2x ![](https://iknow-pic.cdn.bcebos.com/d0c8a786c9177f3ecb83c4be73cf3bc79e3d56c9?x-bce-process=image%2Fresize%2Cm_lfit%2Cw_600%2Ch_800%2Climit_1%2Fquality%2Cq_85%2Fformat%2Cf_auto) ,而根据对数函数定义域可知,2-x>0,x<2,要使得原式有意义则需要满足 ![](https://iknow-pic.cdn.bcebos.com/b64543a98226cffceead8701ba014a90f703eafa?x-bce-process=image%2Fresize%2Cm_lfit%2Cw_600%2Ch_800%2Climit_1%2Fquality%2Cq_85%2Fformat%2Cf_auto) ,故可知答案为B. 点评:主要是考查了函数的定义域的求解,属于基础题。 |
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