[mashinsazi]

I have assembled a Mass and Stiffness matrices that don't lead me to the clear answer because my Mass and Stiffness matrices have zero and infinite determinant. I'm completely confused, I have run my program in MATLAB for different meshes and different properties but error still exist.
I don't why this happen. Can anyone help me about it?

note: I don't know whether it's important or not, but I used meshless method to assemble these matrices.