$1\mathrm{.}64.$ At a specified point in a member, the state of stress with respect to a Cartesian coordina

system is given by

$\left[\begin{array}{ccc}12& 6& 9\\ 6& 10& 3\\ 9& 3& 14\end{array}\right]$MPa

$1\mathrm{.}67.$ Determine the stresses with respect to the $x^{\text{'}},y^{\text{'}},z^{\text{'}}$ axes in the element of Prob. $1\mathrm{.}64$ if

$l_1=\frac{1}{2},l_2=-\frac{\sqrt[\phantom{2}]{3}}{2},l_3=0$

$m_1=\frac{\sqrt[\phantom{2}]{3}}{2},m_2=\frac{1}{2},m_3=0$

$n_1=0,n_2=0,n_3=1$