if:
sin(x+pi/2) - cos(x²) = 0
sin(x+pi/2)=cos(x²)
sin(x+pi/2)=cosx
cosx=cos(x²)
there is infinity answers, along x=0
but if it was
sin(x+pi/2) - cos²x = 0
then
cosx= cos²x
x1= 0
x2= pi/2
