设P(x,y)则x²/25+y²/16=1故y²=16(1-x²/25)故|PA|²=(x-m)²+(y-0)²=x²-2mx+m²+16-16x²/25=9x²/25-2mx+m²+16二次函数,对称轴x=25m/9易知x范围是[-5,5]故...