# Math Help - how to build a 3*3 matrix for given eigenvalues

1. ## how to build a 3*3 matrix for given eigenvalues

like, lambda1=lambda2=lambda3=2
lambda1=1,lambda2=2,lambda3=3

2. $\begin{pmatrix} 1 & 0 & 0 \\ 0 & 2 & 0 \\ 0 & 0 & 2 \end{pmatrix}$ for the first example.