I want to take the inverse of cn2 so that I could do: cn1*cn2^-1

cn1 = SparseArray[{{m_, m_} -> 
     1/2 + 1/2*\[Mu] + 1/2*rr1*\[CapitalDelta]t, {m_, l_} /; 
      l - m == 1 -> -(1/4)*\[Mu] - 1/2*rr1*\[Alpha], {m_, l_} /; 
      m - l == 1 -> -(1/4)*\[Mu] + 1/2*rr1*\[Alpha]}, {101, 101}];
(*from V^(n+(1/2) )to V^n*)

cn2[k3_, n_] = 
  SparseArray[{{m_, m_} -> 
     3/2 + 1/2*\[Mu] + 1/2*rr1*\[CapitalDelta]t, {m_, l_} /; 
      l - m == 1 -> -(1/4)*\[Mu] - 1/2*rr1*\[Alpha], {m_, l_} /; 
      m - l == 1 -> -(1/4)*\[Mu] + 1/2*rr1*\[Alpha], {101, 101}}];