f(x)=(log2x/4)(log2x/2)的最小值
问题描述:
f(x)=(log2x/4)(log2x/2)的最小值
答
f(x)=(log2x/4)(log2x/2)=[log(2)x-log(2)4][log(2)x-log(2)2]=[log(2)x-2][log(2)x-1]=log(2)²x-3log(2)x+2设t=log(2)x ,t∈Ry=t²-3t+2=(t-3/2)²-1/4∴t=3/2时,即log(2)x=3/2,x=2√2时,y=f(x)取得最...