双纽线:r2=a2cos2e du 1 2(c0s20)12 de- a +3sin26(c0s20)512 比耐公式:F=-mL2u2 du dex a' cos 20 1-a+ 2(c0s20)-12+3sin2(c0s20)352 a√cos20 3mL2(r2 7/2 3mL 7 3ma L 3-(os2))22 2 a a a7 4 7 7 / 2 2 2 3 2 7 / 2 3 2 1/ 2 2 5/ 2 2 2 2 2 2 2 1/ 2 2 5/ 2 2 2 2 2 r 3ma L a r a 3mL (cos 2 ) a 3mL a cos 2 1 [2(cos 2 ) 3sin 2 (cos 2 ) ] a 1 a cos 2 mL u d d u F mL u [2(cos 2 ) 3sin 2 (cos 2 ) ] a 1 d d u r a cos 2 = −         = −  = −              +  +    = −         +  = − =  +    =  − − − − − − 比耐公式： 双纽线：