Question

Помогите решить. хелп ми плиз

Answer 1

$displaystyle frac{-4cos26}{cos154}=frac{-4cos26}{cos(pi-26)}= frac{-4cos26}{-cos26}=4;\\\frac{23tg59}{tg121}=frac{23tg59}{tg(pi -59)}=-frac{23tg59}{tg59}=-23;\\\frac{-42sin413}{sin53}= frac{-42sin(2 pi +53)}{sin53}= frac{-42sin53}{sin53}=-42;\\\-22tg14*tg104=-22tg14 *tg( frac{ pi}{2}+14)=-22tg14*(-ctg14)=\=22* frac{sin14*cos14}{cos14*sin14}=22;\\\16tg54*tg36=16tg( frac{pi }{2}-36)*tg36=16ctg36*tg36=16;$

$displaystyle frac{-30}{sin^{2}87+sin^{2}177}= frac{-30}{sin^{2}87+sin^{2}( frac{pi}{2}+87)}=frac{-30}{sin^{2}87+cos^{2}87}=-30;\\\frac{-24}{cos^{2}127+cos^{2}217}=frac{-24}{cos^{2}(frac{pi }{2}+37)+cos^{2}(pi +37)}=\\=frac{-24}{sin^{2}37+cos^{2}37}=-24;\\\frac{4}{sin^{2}57+cos^{2}237}=frac{4}{sin^{2}57+cos^{2}( pi +57)}= frac{4}{sin^{2}57+cos^{2}57}=4; \ \ \ 14sin30*cos120=14* frac{1}{2}*cos( frac{ pi }{2}+30)=7*(-sin30)= \ =7*(- frac{1}{2})= -3,5;$