求极限lim(x→π/4) 1+sin2x/1-cos4x

x→π/4时,直接代入,得sin2x→1,cos4x→-1则极限为1我想题目可能是lim(x趋于派/4) 1-sin2x/1+cos4x=lim 1-cos(π/2-2x)/1-cos(π-4x)=lim (1/2)(π/2-2x)² / (1/2)(π-4x)²=lim (1/4)(π-4x)² / (π-...