This is not a continuous function. The relationship holds only for the discrete points (k) specified. To synthesize the lengths of the links needed to satisfy equation 5.36. we will write vector loop equations around the linkage in pairs of positions, as was done for the previ- ous examples. However, we now wish to include both link 2 and link 4 in the loop, since link 4 is the output. See Figure 5-10.