1.若$a=200$,$b=lg{\left( 101 \right)}^{99}$,$c=101lg99$,则$a$、$b$、$c$的大小关系为( )
A.$a>c>b$ B.$c>a>b$
C.$c>b>a$ D.$a>b>c$
解 设$f\left( x \right)=\left( 100-x \right)lg\left( 100+x \right)$,$x \in \left[ -1,1 \right]$,
当$x \in \left[ -1,1 \right]$时,${f}^{'}\left( x \right)=-lg\left( 100+x \right)+\frac{100-x}{100+x}lg\text{e}$,
令$g\left( x \right)=-lg\left( 100+x \right)+\frac{100-x}{100+x} \cdot lg\text{e}$,则${g}^{'}\left( x \right)=-\frac{1}{100+x}lg\text{e}-\frac{200}{{\left( 100+x \right)}^{2}}lg\text{e}<0$,
所以函数$g\left( x \right)$在区间$\left[ -1,1 \right]$上单调递减,
所以$g\left( -1 \right)=-lg99+\frac{101}{99}lg\text{e}=lg{\text{e}}^{\frac{101}{99}}-lg99$,
又${\text{e}}^{\frac{101}{99}}<{\text{e}}^{2}<99$,所以${f}^{'}\left( x \right)=g\left( x \right)<g\left( -1 \right)<0$,
所以函数$f\left( x \right)$在区间$\left[ -1,1 \right]$上单调递减,
所以$f\left( -1 \right)=101lg99>f\left( 0 \right)=100lg100=200>f\left( 1 \right)=99lg101=lg{\left( 101 \right)}^{99}$,
故$c>a>b$.
故选:B.
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