Q=b2:b1=-250/(-1250)=1/5
b1•(q^5–1) -1250•(1/3125–1)
S5 = --------------- = ----------------------- =
q–1 -4/5
-7/5
= ------- = (7•5)/(5•4) = 7/4
-4/5
sin(a+6pi)ctg(5pi-a)/sin(2pi-a)ctg(5pi+a)=sina(-ctga)/{(-sina)ctga}=1
1) -2v5+v5=-v5
-2v5-v5=-3v5
-2v5*v5=-2*5=-10
-2v5\v5=-2
2)=5v5+3v5-4v3=4v5
3)=(v13)^2-(3v3)^2=13-27=-14-целое