Can anyone help me to get a weak form coding for equation:

u_x * T_y - u_y * T_x = 0 ---------------------(1)

The weak form as for test fn w is:

- w_x * u * T_y + w_y * u * T_x = 0 ---------------------------(2)

And I have written the code for equation (2) as:

`- dx(w) * u * dy(T) + dy(w) * u * dx(T)`

But it shows some error for linearity.

KINDLY SUGGEST ME TO FIX IT.