y=1/(-x²+2x-5)-x²+2x-5=1/y-(x²-2x+5)=1/y-(x²-2x+1+4)=1/y-(x²-2x+1)-4=1/y-(x-1)²-4=1/y∵(x-1)²≥0∴-(x-1)²-4≤-4∴1/y≤-4∴-1/4≤y<0∴值域是[-1/4,0)如果您认可我的回答，请点击“采纳为满意答案”,祝学习进步！
