Question

алгебра помогите решить скрин прилагается

Answer 1

$6); ; tg(-frac{pi}{4})+cos(-frac{pi}{4})+sin(-frac{pi}{4})=-tgfrac{pi}{4}+cosfrac{pi}{4}-sinfrac{pi}{4}=\\=-1+frac{sqrt2}{2}-frac{sqrt2}{2}=-1\\\7); ; sin(-frac{pi}{6})- cos(-frac{pi}{3})-tg(-frac{pi}{6})=-sinfrac{pi}{6}-cosfrac{pi}{3}+tgfrac{pi}{6}=\\=-frac{1}{2}-frac{1}{2}+frac{sqrt3}{3}=frac{sqrt3}{3}-1$

$8); ; sin(-frac{3pi}{2})+cos(-11pi )=-sinfrac{3pi}{2}+cos11pi =-(-1)+cos(underbrace {5cdot 2pi }_{period}+pi )=\\=1+cospi =1-1=0\\\9); ; tg(-780^circ )-ctg(-390^circ )=-tg(underbrace {4cdot 180^circ }_{period}+60^circ )+ctg(underbrace {2cdot 180^circ }_{period}+30^circ )=\\=-tg60^circ +ctg30^circ =-sqrt3+sqrt3=0$