Question

Помогите решить
$14\sqrt{2} sin \frac{ \pi }{6}*cos(- \frac{3 \pi }{4})$

Answer 1

$14 \sqrt{2} * \frac{1}{2} *cos( \pi - \frac{ \pi }{4} )=14 \sqrt{2}* \frac{1}{2} (-cos \frac{ \pi }{4} )= 14 \sqrt{2} * \frac{1}{2} *(- \frac{ \sqrt{2} }{2} )=-7$