Question

sin 22,5 * cos 157,5

Answer 1

$sin 22.5^0*cos 157.5^0=sin22.5^0*cos(180^0-22.5^0)=$
$=sin 22.5^0*(-cos 22.5^0)=-0.5*2sin 22.5^0*cos 22.5^0=$
$-0.5*sin (22.5^0*2)=-0.5*sin45^0=-0.5*frac{sqrt{2}}{2}=-frac{sqrt{2}}{4}$

Answer 2

спасибо большое)