cos(x/2 +pi/4)+1=0
cos(x/2 +pi/4)=-1
x/2 +pi/4=pi+2*pi*n
x/2=pi-pi/4+2*pi*n
x=2pi-pi/2 +4*pi*n
x=3pi/2 +4*pi*n
cos(x/2 +pi/4)+1=0
cos(x/2 +pi/4)=-1
x/2 +pi/4=pi+2*pi*n
x/2=pi-pi/4+2*pi*n
x=2pi-pi/2 +4*pi*n
x=3pi/2 +4*pi*n