Question

In basic equation Lu=f, L is a ____________

(a) Matrix function

(b) Differential operator

(c) Degrees of freedom

(d) No. of elements

The question was asked in quiz.

This intriguing question originated from One Dimensional Problems topic in chapter One Dimensional Problems of Finite Element Method

Answer 1

The correct option is (b) Differential operator

For explanation I would say: The method of weighted residual technique uses the weak form of physical problem or the direct differential equation. The basic equation Lu=f in that L is an differential operator. It uses the principle of orthogonality between Residual function and basis function.