meili 发表于 2022-10-27 15:03:36

已知函数f(x)=log4(4^x+1)+kx是偶函数,解不等式f(x)>1

<p>问题:已知函数f(x)=log4(4^x+1)+kx是偶函数,解不等式f(x)>1
<p>答案:↓↓↓<p class="nav-title mt10" style="border-top:1px solid #ccc;padding-top: 10px;">梁宏伟的回答:<div class="content-b">网友采纳  偶函数f(-x)=f(x),  log4-kx=log4(4^x+1)+kx,  log4{/(4^x+1)}=2kx,  log41/4^x=2kx,  -x=2kx,  k=-1/2,  f(x)>1,-->log4(4^x+1)-x/2>1,  log4(4^x+1)>x/2+1,  4^x+1>4^(x/2+1),  (2^x)²-4*2^x+1>0,  2^x>1+√3/2或2^xlog2(1+√3/2)或x
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