g(x)=-2lnx-2x*1/x+2x-2a=-2lnx+2x-2a-2则g'(x)=-2/x+2所以就看g'(x)的符号显然由lnx则x>0g'(x)=2(1-1/x)=2(x-1)/xx>0所以0x>1，g'(x)>0，g(x)递增
