1／ab＝1／4ab=41/a²＋1／b²＝3(a²+b²)/(a²b²)=3a²+b²=3a²b²=3*4²=48(a+b)²/(a²+b²)=(a²+b²+2ab)/(a²+b²)=(48+2*4)/(4...