Subscript[f,
2] = (Subscript[\[Theta], 2] - 1)*
C1*(l*Sin[Subscript[\[CapitalPhi], 1]] - \[Rho]*
Sin[\[Alpha] + Subscript[\[CapitalPhi], 1]]) +
Subscript[\[Theta],
2]*((1 - Subscript[\[CapitalPhi],
2])*(C2*l*
Sin[Subscript[\[Theta], 1] + Subscript[\[CapitalPhi], 1] -
Subscript[\[CapitalPhi], 2]] -
C2*\[Rho]*
Sin[\[Alpha] + Subscript[\[Theta], 1] +
Subscript[\[CapitalPhi], 1] - Subscript[\[CapitalPhi],
2]])) +
C2*Subscript[\[CapitalPhi], 2]*C1*
Sin[Subscript[\[Theta], 1] - Subscript[\[CapitalPhi], 2]] == 0;