Mathematics

Problem

Show that

|\mathbf{a}+\mathbf{b}|^{2}+|\mathbf{a}-\mathbf{b}|^{2}=2\bigl(|\mathbf{a}|^{2}+|\mathbf{b}|^{2}\bigr)

for any vectors

\mathbf{a}

and

\mathbf{b}