Magic of Math#10

$cot(\frac{\pi}{2}-\zeta) = tan(\zeta)$ , hence the question may be written as $\sqrt{(1+\frac{sec^{2}(\zeta)-tan^{2}(\zeta)}{cosec(\theta)})(1-\frac{tan(\theta)}{sec(\theta)})}$ or in a more simplified form as $\sqrt{(1+sin(\theta))(1-sin(\theta))}$ which may be put further to $\sqrt{1-sin^{2}(\theta)}$ , an equivalent to $|cos(\theta)|$ . Given that $0 < \theta < \frac{\pi}{2}$ , the value may be released from the absolute value as $cos(\theta) = \frac{2}{7}$ , hence $sec(\theta) = \frac{7}{2}$