(20)
| −zY = A | dp | − Apq cot θ + qh3, |
| dt |
(21)
| −zX − xZ = A | dq | + Ap2 cot θ − ph3, |
| dt |
| xY = | dh3 | = C | dr | = −Cq | d | . |
| dt | dt | dθ |
(23)
Eliminating Y between (19) and (23),
| ( | C | + x2 ) | dr | − xz | dp | + pqx (x + z cot θ − ρ sin θ) − qrxρ cos θ = 0, |
| M | dt | dt |
(24)
| ( | C | + x2 ) | dr | − xz | dp | − px (x + z cot θ − ρ sin θ) + rxρ cos θ = 0. |
| M | dθ | dθ |