I need to prove the next statement:
Let be an operator that its coefficients A,B,C,D,E are continiously differentiable twice in the plane.
Show (directly from the definition of an adjoint of an operator) that .
The definition of an adjoint of an operator is+my problem:
Hope you'll be able to help me !
My problem is , that when I substitute L* in the expression for the adjoint, I get partial derivatives of fourth order!!! how can I prove this equality using only this definition?
Thanks in advance