I'm not sure but I'm going to assume that you are finding for the value of theta. If this is correct, the solution would be
\(\sqrt{3} tan3 \alpha \ -1=0\)
\(\ tan3 \alpha = \frac{1}{\sqrt{3}}\)
\(3 \alpha = arctan ( \frac{1}{ \sqrt{3} } )=30\)
\(\alpha = 30/3=10\)
Fyi, there is no theta in the symbols so I just used alpha.
Thus, theta is equal to 10 degrees.
