evaluating the integral:

$$$3$$6$cos$($$)31$sin$($$)$d$\backslash$int$\_\{\backslash$frac$\{\backslash$pi$\}\{3\}\}^\{\backslash$frac$\{\backslash$pi$\}\{6\}\}\backslash$frac$\{\backslash$cos$(\backslash$theta$)\}\{3\backslash$sqrt$\{1-\backslash$sin$(\backslash$theta$)\}\}\backslash ,$ d$\backslash$theta$3$$6$$31$sin$($$)$cos$($$)$d