Question

if 1-tan square theta =2/3 then what is the value of theta

Answer 1

Please assume alpha as theta, coz there is no theta button in the equation inserter.
$1 - { \tan}^{2} \alpha = \frac{2}{3} \\ { \tan}^{2} \alpha = 1 - \frac{2}{3} = \frac{1}{3} \\ \tan \alpha = \frac{1}{ \sqrt{3} } \\ \tan \alpha = \tan30 \\ \alpha = 30$