設橢圓xx/aa + yy/bb = 1(a>b>0)與直線x+y=1相交于P,Q兩點,且OP⊥OQ(O為原點)(1)求1/aa + 1/bb的值(2)若橢圓的離心率滿足(√3)/3 ≤e≤ (√2)/2,求橢圓長軸的取值范圍