Equations 5.25 and 5.26 solve the three-position synthesis problem for the left-hand
side of the linkage using any pair of assumed values for rl2 and rl3. We must repeat the
above process for the right-hand side of the linkage to find vectors U and S. Figure 5-4
(p. 202) also shows the three positions of the US dyad, and the angles 0', 12, 13, "', u2,
and u3, which define those vector rotations for all three positions. The solution deriva
tion for the right-side dyad, US, is identical to that just done for the left dyad WZ. The
angles and vector labels are the only difference. The vector loop equations are