易知,(9/m²)+(1/n²)=1.且m≠n.∴由基本不等式可得:m²+n²=[(9/m²)+(1/n²)](m²+n²)=10+(9n²/m²)+(m²/n²)≥10+6=16.即m²+n²≥16.∴(m²+n²)min=16.