Compute the stiffness matrix D^-1 for D in Exercise 49. List the forces needed to produce a deflection of .04 in. at point 3, with zero deflections at the other points.

Data from in Exercise 49

Letbe a flexibility matrix, with flexibility measured in inches per pound. Suppose that forces of 30, 50, and 20 lb are applied at points 1, 2, and 3, respectively, in Figure 1 of Example 3. Find the corresponding deflections.

Data from in Figure 1

D = .005 .002 .001 .002 .004 .002 .001 .002 .005