Question

6√6sin 3π/4 * cos7π/6

Answer 1

$6 sqrt{6}sin frac{3 pi }{4}*cos frac{7 pi }{6}=$
$=6 sqrt{6}sin( frac{ pi }{2}+ frac{ pi }{4} )*cos( pi + frac{ pi }{6} )=$
$=6 sqrt{6}cos frac{ pi }{4}(-cos frac{ pi }{6} )=$
$=-6 sqrt{6}* frac{ sqrt{2} }{2} *frac{ sqrt{3} }{2}=-9.$