I have to compute a formula, this one:
However I don't know the calculus order between the big circle and the small one and I am also not quite sur about what these symbols mean. each vaiable are 3d points in a plane. could you tell me what is the order and what the symbols mean ?
The thick dot is the inner product or dot product of two vectors, defined by $$ \begin{pmatrix} v_1 \\ v_2 \\ v_3 \end{pmatrix} \bullet \begin{pmatrix} w_1 \\ w_2 \\ w_3 \end{pmatrix} = v_1w_1 + v_2w_2 + v_3w_3. $$ Note that the outcome is a number, not another vector. The double bars give the norm, which is defined by $$ \|v\| = \sqrt{v \bullet v}. $$ Finally, the small dot $\cdot$ is just the multiplication of two numbers.
If you know what vectors of the letters in your expression stand for, you should now be able to compute the formula.