Trace From Eigenvalues

The trace of a matrix equals the sum of its eigenvalues, counted with multiplicity.

Add the three given eigenvalues directly.

1. 1. Apply the trace-eigenvalue identity

   For any square matrix, the trace equals the sum of its eigenvalues.

   $$\text{tr}(A)=2+4+5$$

2. 2. Add

   Summing the eigenvalues gives the trace.

   $$\text{tr}(A)=11$$

Answer: 11