\(l1\  = \ 1.0; 
l2\  = \ 1.0; 
l3\  = \ 1.0; 

    J[t1_, t2_, t3_]\  := 
      \ {{\(-l1\)\ Sin[t1]\  - \ l2\ Sin[t1\  + \ t2]\  - \ 
\ \ \ \ \ \ \ \ 
            l3\ Sin[t1\  + \ t2\  + \ t3], \ 
          \(-l2\)\ Sin[t1\  + \ t2]\  - \ 
\ \ \ \ \ \ \ \ 
            l3\ Sin[t1\  + \ t2\  + \ t3], \ 
          \(-l3\)\ 
\ \ \ \ \ \ \ \ Sin[t1\  + \ t2\  + \ t3]}, 
        \ {
\ \ \ \ \ \ 
          l1\ Cos[t1]\  + \ l2\ Cos[t1\  + \ t2]\  + \ 
            l3\ Cos[t1\  + \ t2\  + \ t3], \ 
\ \ \ \ \ \ 
          l2\ Cos[t1\  + \ t2]\  + \ l3\ Cos[t1\  + \ t2\  + \ t3], \ 

          \ \ \ \ \ \ l3\ Cos[t1\  + \ t2\  + \ t3]}}; 

    Print[Eigensystem[
        J[0.1, 0.1, \(-0.1\)]\  . \ Transpose[J[0.1, 0.1, \(-0.1\)]]]]; \)