N<a<3n/2(3 четверть)
sina=-(1-cos^2a)(Все это под корнем кроме sina)=-(1-0.36)=-(0.64)=-0.8(корень числа 0,64=0,8)
Ставиться минус потому, что sina 3 четверти отрицательный
1) My parnts know so much because they have already travelled a lot.
2) We haven't seen George since last year.
3) I haven't seen this film yet.
4)Alice has just met her friend.
6) The kids have just played in the yard
5) I have never spoken to our teacher.
7) We haven't decided to help him yet.
8) I haven't seen my family for a long time.
9) Have you ever ridden the scooter.
10) Sara has never been snorkelling. She is so inactive!
(3*а^2*b^4)/ (1/3*a*b^3)= (3*а^2*b^4*3)/( a*b^3)=9*a*b
ответ:9*а*b
Sinxcosx+cos^2x-1>0
sinxcosx+cos^2x-cos^2-sin^2x>0
sinxcosx-sin^2x>0
sinx(cosx-sinx)>0
sinx>0 Пk<x<П+Пk
tgx<1 -П/2+Пk<x<П/4+Пk
2Пk<x<П/4+2Пk
sinx<0
tgx>1
5П/4+2Пk<x<3П/2+2Пk
2Пk<x<П/4+2Пk U 5П/4+2Пk<x<3П/2+2Пk