Constant Energy and Length

We demand now that the dimensionless total energy and the dimensionless total length tot should be constant. Further, we deal with two springs only. In this case, we have now the following two equations  

We have only two variables fi and I2 in these two equations. Therefore, we could have one unique solution in a linear set of equations and since one of the equations is quadratic and the equations are completely symmetric with respect to i, 2 we 

We show the situation in Fig. 2.4. The isodynamic curves are forming circles around the origin, whereas the curves of equal dimensionless length are straight lines with a slope of -1. 

The graphical representation of Fig. 2.4 can be easily extended in three dimensions. In three dimensions, the dimensionless isodynamic curves are now spheres 

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