f(x)=2x²-lnx求导f'(x)=4x-(1/x)=(4x²-1)/x=(2x-1)(2x+1)/x定义域x>0f'(x)>0得x>1/2所以单调增区间为 (1/2,正无穷)单调减区间为 (0,1/2)
