(1)xxB=1/3→>R(25%处) (2)R→R(?RRS交平衡线) (3)R→>E(KA=1,连结线与BS平行) (4)RE和FS相交得M 5)杠杆法则求S (6)→>E(?SEE’) (7)杠杆法则求E解答 (1) xA/xB=1/3 → R’(? 25%处) (2) R’ → R (? R’RS交平衡线) (3) R → E (? KA=1, 连结线与BS平行) (4) RE和FS相交得M (5) 杠杆法则求S (6) E → E’(? SEE’) (7) 杠杆法则求E’