1. sinx=-(sqrt2)/2, x=((-1)^(n+1))*(pi/4) +pi n
2. cos(x/2 + pi/4)=-1, x/2 + pi/4=pi+2 pi n, x/2 = pi/4 - pi +2 pi n,
x/2 = - (3pi/4) + 2pi n, x=-3pi/2 + 4pi n
1. sinx=-(sqrt2)/2, x=((-1)^(n+1))*(pi/4) +pi n
2. cos(x/2 + pi/4)=-1, x/2 + pi/4=pi+2 pi n, x/2 = pi/4 - pi +2 pi n,
x/2 = - (3pi/4) + 2pi n, x=-3pi/2 + 4pi n