ТРИГОНОМЕТРИЯ ПОМОГИТЕ ПОЖАЛУЙСТА)

1)
$3 \sqrt{2} *sin \frac{3 \pi }{8} *cos \frac{3 \pi }{8}=3 \sqrt{2}* \frac{1}{2} *(2 *sin \frac{3 \pi }{8} *cos \frac{3 \pi }{8})=$ $= \frac{3 \sqrt{2} }{2} *sin(2* \frac{3 \pi }{8}) = \frac{3 \sqrt{2} }{2} *sin \frac{3 \pi }{4}= \frac{3 \sqrt{2} }{2} *sin( \pi - \frac{ \pi }{4}) = \frac{3 \sqrt{2} }{2} *sin \frac{ \pi }{4}=$ $= \frac{3 \sqrt{2} }{2} * \frac{ \sqrt{2} }{2}=1.5$

2)
$\frac{23(sin^288к-cos^288к)}{cos176к}= \frac{-23(cos^288к-sin^288к)}{cos176к} = \frac{-23*cos(2*88к)}{cos176к} =$ $\frac{-23*cos176к}{cos176к} =-23$

3)
$tgj=0.2$
$2tg(-4 \pi +j)-3tg(-j)=-2tg(4 \pi-j)+3tgj=2tgj+3tgj=5tgj$
$5tgj=5*0.2=1$

$2sinx*cosx=sin2x$
$cos^2x-sin^2x=cos2x$