Cos(5)Cos(55)Cos(65)=sin(5pi/36)sin(7pi/36)cos(5*)
Решение:
18-0,6х+14=х
х+0,6х=-14-18
1,6х=-32
х=20
B1q-b1=3/4 b1(q-1)=3/4
b1q^3-b1q^2=3/196 b1q^2(q-1)=3/196
(3/196)*(4/3)=q^2
1/49=q^2
q=1/7 q=-1/7
q-1=-6/7 q-1=-8/7
b1=-(3/4)*(7/6)=-7/8 b1=-(3/4)*(8/7)=-6/7