W equals wing lift.
D subscript W equals distance.
T equals tail lift.
D subscript T equals distance.
CG equals center of gravity.
For trimmed flight, no rotation about or around CG.
Equation: (D subscript w multiplied by W) plus (D subscript T multiplied by T) equals zero.
(distance from CG multiplied by Lift of Wing) plus distance from CD multiplied by Lift of Tail) equals zero.