Question

[Peter]

Hello,

When polar decomposition is applied to a deformation-gradient tensor ( F )
it can be split into a right stretch tensor ( U ) and a rotation tensor
( R ).

These steps have to be followed:
1. calculate C = F^c dot F
2. calculate eigenvalues en eigenvectors of C
3. then U is known, as well as U^(-1)
4. calculate R = F dot U^(-1)

Can somebody explain step 3 (how can U be derived  from step 2 ?)
Do you need to use the spectral form of the tensor C ?
Can someone explain it with an example ?

Thanx a lot !

PS I don't know wether this is the right newsgruop for this question. Are
there more suitable groups ??