would it make more sense to you if they used "c" instead of "b"? it's just a place-holder, any symbol could have been used.
I have to show 0= T(A)=A+A^T
A=[a b].
///[c d]
I got it to where [2a c+b]=[0 0]
///////////////////[b+c 2d]//[0 0]
I know a=d=0 and b=-c. but then i can seem to figure out why the answer is
ker T={[0 -b]
////////[b 0] where b is a real number}
how do they get that?