Նարեկ Ներսիսյան

Վարժ. 131 ա) sin27°cos3°+cos27°sin3°=sin30°=1/2=0,5 բ) cos87°cos27°+sin87°sin27°=cos60°=1/2=0,5 Վարժ. 132 ա)(sin π/15 +cos π/10)² + (cos π/15 +sin π/10)²=3 sinπ/15² + 2sinπ/15cos×π/10 + cosπ/10²+cosπ/15²+2cosπ/15×sinπ/10 + sin π/10²=2+( 1/2 -sinπ/30)+( 1/2 +sinπ/30)=2+ 1/2 -sinπ/30+1/2+sinπ/30=3 բ) (cos π/9 -cos 2π/9)² + (sin π/9 +sin… Continue Reading →