I have the matrix H:
A11=a+bi
A12=c+di
A21=-c+di
A22=a-bi
I need to show that the equation x^2=-1 has infinitely many solutions in H.
I ignored a (because the book told me to) and so I have the matrix:
A11=bi
A12=c+di
A21=-c+di
A22=-bi
where b^2+c^2+d^2=1.
I'm just having trouble showing the "infinitely many solutions in H" part.