Question Number 162411 by HongKing last updated on 29/Dec/21
![Prove the identity for any ′n′ in Real number [(n/2)] ∙ [((n + 1)/2)] = (1/4)([n]^2 + 2[(n/2)] - [n]) [∗] Greatest Integer Function](Q162411.png)
$$\mathrm{Prove}\:\mathrm{the}\:\mathrm{identity}\:\mathrm{for}\:\mathrm{any}\:'\boldsymbol{\mathrm{n}}'\:\mathrm{in}\:\mathrm{Real}\:\mathrm{number} \\ $$$$\left[\frac{\mathrm{n}}{\mathrm{2}}\right]\:\centerdot\:\left[\frac{\mathrm{n}\:+\:\mathrm{1}}{\mathrm{2}}\right]\:=\:\frac{\mathrm{1}}{\mathrm{4}}\left(\left[\mathrm{n}\right]^{\mathrm{2}} \:+\:\mathrm{2}\left[\frac{\mathrm{n}}{\mathrm{2}}\right]\:-\:\left[\mathrm{n}\right]\right) \\ $$$$\left[\ast\right]\:\mathrm{Greatest}\:\mathrm{Integer}\:\mathrm{Function} \\ $$