1)sin7°cos23°+sin23°cos7°+3=? 2)sin60°cos26°+cos64°sin26°-sin30°=? - вопрос №1723237326026642630383800688 от Alferd 22.10.2022 17:41

Question

Алгебра: 1)sin7°cos23°+sin23°cos7°+3=? 2)sin60°cos26°+cos64°sin26°-sin30°=? 3)8sin25°sin65°деленное дробной чертой на cos40°=? 4)tg12°+tg33° деленное дробной чертой на 1-tg12°tg33°

Alferd · Answer

1) ...=sin(7°+23°)  +3 = sin30°+3= 3,5 ;2) ... = sin( 64°+ 26°)- 1/2 =sin90° -1/2= 1-1/2  =1/2 ;3)  ...= 8sin25°*sin(90° -25°)/cos40° =8sin25°*cos25° /cos40° =4sin50 °/cos40° ==4sin(90°-40°)/cos40° =4cos40°/cos40° =4  ;4) ...= (tq12°+tq33)°/(1-tq12°*tq33° =tq(12°+33°) =tq45° =1 ....