(2)For中2-43=π 2cos4,+(4+l)c0sp2=4 2sin+(4+1)sin=2-1 4+(4+)2+4(4+)cos(-p2)=16+(2-1)2 (4+1)cos(,-42)=-31 Since cos(,-中2≤1 1≤2 For 1=2 cos(0,-p2)=1 中1=π+中2 C0s,=-1 41=43=π,中2=0 008 Bifurcation For /<2 cos(4-φ2)=-31/(4+1) =2 -arccos 31/(4+1) Lock-up(2) For l l l 2sin (4 )sin 2 2cos (4 ) cos 4 1 2 1 2 f f f f f2 f3 2 1 2 2 4 (4 l) 4(4 l) cos(f f ) 16 (2 l) (4 l) cos( ) 3l f1 f2 Since cos(f1 f2 ) 1 l 2 For l = 2 cos(f1 f2 ) 1 f1 f2 For l < 2 cos( ) 3 /(4 ) 1 2 f f l l cosf1 1 f1 f3 , f2 0 arccos3 /(4 ) 1 2 f f l l w w Bifurcation Lock-up