Inversion of Stiffness Equations

Before the predicted stiffnesses are compared with measured stiffnesses, however, a slight reinterpretation of laminate stiffnesses is 

However, in most experiments, the loads are applied, and the resulting deformations are measured, i.e., the deformations are the dependent variables, not the loads. Thus, the expressions for the middle-surface extensional strains and curvatures in terms of the force and moment resultants would be convenient. 

The first step in the derivation of the inverse of Equation (4.62) is to write it in the form 

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