and dividing out sin θ, which equated to zero would imply perfect centring, we obtain
| C2μ2 cos θ − C1pμ + (c2 − c1) | c1 | u2 sec θ = 0. |
| c2 |
(6)
The least admissible value of p is that which makes the roots equal of this quadratic in μ, and then
| μ = ½ | C1 | p sec θ, |
| C2 |
(7)
the roots would be imaginary for a value of p smaller than given by
| C12p2 − 4 (c2 − c1) | c1 | C2u2 = 0, |
| c2 |
(8)
| p2 | = 4 (c2 − c1) | c1 | C2 | . | |
| u2 | c2 | C12 |