Question

函數(shù)y=

1

log5(2x-1)

的定義域是（　�。�

• A、{x|x＞

  1

  2

  }
• B、{x∈R|x≠

  1

  2

  }
• C、{x∈R|x≠1}
• D、{x|x＞

  1

  2

  且x≠1}

Answer 1

分析：令對(duì)數(shù)的真數(shù)大于0且分母非0即對(duì)數(shù)的真數(shù)不為1，列出不等式組求出x的范圍即函數(shù)的定義域．

解答：解：要使函數(shù)有意義，需使

2x-1＞0 2x-1≠1

解得x＞

1

2

且x≠1
故選D

點(diǎn)評(píng)：求解析式已知的函數(shù)的定義域，一般要考慮開偶次方根的被開方數(shù)大于等于0；對(duì)數(shù)的真數(shù)大于0底數(shù)大于0且不等于1；分母非零．