(6)
| dP | = | dl | x1 + | dm | x2 + | dn | x3 |
| dt | dt | dt | dt |
| + l | dx1 | + m | dx2 | + n | dx3 | , |
| dt | dt | dt |
| = l ( | dx1 | − x2R + x3Q ) |
| dt |
| + m ( | dx2 | − x3P + x1R ) |
| dt |
| + n ( | dx3 | − x1Q + x2P ) |
| dt |
= lX + mY + nZ,
(7)
for all values of l, m, n.
Next, taking a fixed origin Ω and axes parallel to Ox, Oy, Oz through O, and denoting by x, y, z the coordinates of O, and by G the component angular momentum about Ω in the direction (l, m, n)