ANSWER
[tex]\begin{gathered} c)s\imaginaryI n\frac{\theta}{2}=\sqrt{\frac{1}{2}(1-\frac{\sqrt{13}}{7})} \\ decimal=0.49 \\ d)cos\frac{\theta}{2}=\sqrt{\frac{1}{2}(\frac{\sqrt{13}}{7}+1)} \\ decimal=0.87 \end{gathered}[/tex]
EXPLANATION
Given;
[tex]\begin{gathered} sin\theta=\frac{6}{7} \\ 0<\theta<\frac{\pi}{2} \end{gathered}[/tex]
c) Hence;
[tex]\begin{gathered} sin\frac{\theta}{2}=\sqrt{\frac{1}{2}(1-\frac{\sqrt{13}}{7}}) \\ \end{gathered}[/tex]
In decimal form;
[tex]sin\frac{\theta}{2}=0.49[/tex]
d)
[tex]\begin{gathered} cos\theta=\frac{\sqrt{13}}{7} \\ cos\frac{\theta}{2}=\sqrt{\frac{1}{2}(\sqrt{\frac{13}{7}+1})} \\ decimal=0.87 \end{gathered}[/tex]
