Answer:
Optical axis
Step-by-step explanation:
Optical axis is the rotational symmetry axis of the surfaces.
A line with a certain degree of rotational symmetry is called as the optical axis in an optical system.
It is the straight line that passes through the geometric center of the lens and joins two curvature centers of its surfaces.
It is also called as the principal axis.
Answer:
it will be 1/2
Step-by-step explanation:
because x×y={(6,2), (6, 8),(9,2), (9, 8)}
Divide both sides by -3, and replace 
with 
. Then
Factorize the quadratic in to get
which in turn means
But 
for all real 
, so we can ignore the first solution. This leaves us with
If we allow for any complex solution, then we can continue with the solution we ignored:
