xB=21cos0, yeIsn 0, y=3lsin 0 axg =-2lsin 000, Svc=lcos 600, Sg=3l cos 008 代入虚功方程得: FR- (2lsin 680+koolcos680-koo 3L cos58 +f3l cos 000=0 解得: fcote-ko cot exB = −2lsin , yC = l cos, yG = 3l cos xB = 2l cos, yC = lsin , yG = 3lsin  3 cos 0 ( 2 sin cos 3 cos 0 0 + = − + −       F l F l k l k l Bx 代入虚功方程得： cot  cot 2 3 0 F F k 解得： Bx = −