Let $A = \left[\begin{array}{ccc} 6 &-4 &-14\cr -6 &4 &14\cr 3 &-4 &-11 \end{array}\right]$.

Find $S$ and $D$ such that $A=SDS^{-1}$.

$S=$

$\left[\Rule{0pt}{3.6em}{0pt}\right.$$\left]\Rule{0pt}{3.6em}{0pt}\right.$

, $D=$

$\left.\vphantom{\begin{array}{c}\!\strut\\\!\strut\\\!\strut\\\!\strut\\\end{array}}\right[$ 0 0 $\left.\vphantom{\begin{array}{c}\!\strut\\\!\strut\\\!\strut\\\!\strut\\\end{array}}\right]$ 0 0 0 0

.