Mathematics

Problem

Which of the following statements holds for any two vectors

\mathbf{p}

and

\mathbf{q}

? a)

\mathbf{p}+\mathbf{q}=\mathbf{q}-\mathbf{p}

\mathbf{p}+\mathbf{q}=-(\mathbf{q}+\mathbf{p})

\mathbf{p}+\mathbf{q}=\mathbf{q}+\mathbf{p}

\mathbf{p}+\mathbf{q}=\mathbf{p}\times\mathbf{q}