1
(cos(720+60)-ctg(540-45))*sin(180+45)=(cos60-ctg(-45))*(-sin45=
=(1/2+1)*(-√2/2=-3√2/4
-sin(4π-π/4)*tg(3π+π/6)=sinπ/4*tgπ/6=√2/2*√3/3=√6/6
2
2sina/(-sina)=-2
(5^12 * 3^12 * 3^2) / 15^14 =
= (15^12 * 3^2) / 15^14 =
= 9 / 225 = 1/25= 0, 01
1) a1=1 n=50 a50=20
S(50)=((a1+a50)/2)*50=((1+20)/2)*50=(21/2)*50=21*25
S(50)=525
2) S(100)=((1+200)/2)*100=(201/2)*100=201*50
S(100)=10050
вроде бы не ошибаюсь.